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+# DESIGN-0.16.0 — User Groups + Resource Grants
+
+## Overview
+
+The missing access-control primitive. Teams define organizational structure
+(horizontal visibility). Roles define vertical permissions (admin/user).
+**Groups** are pure access-control lists that decouple resource access from
+team membership.
+
+Today, resource visibility follows a rigid scope model: `global` (everyone),
+`team` (team members), `personal` (owner only). This breaks down when:
+- A KB should be visible to members from two different teams.
+- A Persona should be accessible by a cross-functional working group.
+- A future Project needs participants from multiple teams.
+
+Groups solve this by adding a fourth access path — grant-by-group — without
+changing the existing scope model. Existing `global/team/personal` access
+continues to work unchanged. Groups are additive.
+
+Depends on: teams (v0.10.0), knowledge bases (v0.14.0).
+
+**Design principle: don't break the scope model.** Groups extend it. Every
+existing query that filters by `scope + owner_id + team_id` remains valid.
+Group membership is a parallel access path checked alongside scope, not a
+replacement for it.
+
+---
+
+## 1. Schema
+
+Migration: `010_groups.sql`
+
+### 1.1 Groups Table
+
+```sql
+-- =========================================
+-- USER GROUPS
+-- =========================================
+
+CREATE TABLE IF NOT EXISTS groups (
+    id          UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    name        VARCHAR(100) NOT NULL,
+    description TEXT NOT NULL DEFAULT '',
+    scope       VARCHAR(20) NOT NULL DEFAULT 'global'
+                CHECK (scope IN ('global', 'team')),
+    team_id     UUID REFERENCES teams(id) ON DELETE CASCADE,
+    created_by  UUID NOT NULL REFERENCES users(id),
+    created_at  TIMESTAMPTZ DEFAULT NOW(),
+    updated_at  TIMESTAMPTZ DEFAULT NOW(),
+
+    -- Global groups: team_id must be NULL
+    -- Team groups: team_id must be set
+    CONSTRAINT groups_scope_team CHECK (
+        (scope = 'global' AND team_id IS NULL) OR
+        (scope = 'team' AND team_id IS NOT NULL)
+    )
+);
+
+CREATE UNIQUE INDEX IF NOT EXISTS idx_groups_name_scope
+    ON groups(name, COALESCE(team_id, '00000000-0000-0000-0000-000000000000'));
+    -- Unique name within scope (global names unique globally,
+    -- team names unique within team)
+
+COMMENT ON TABLE groups IS
+    'Access-control groups. Decouple resource visibility from team membership.';
+COMMENT ON COLUMN groups.scope IS
+    'global: admin-managed, can span teams. team: team-admin-managed, team-internal.';
+```
+
+### 1.2 Group Members Table
+
+```sql
+CREATE TABLE IF NOT EXISTS group_members (
+    id          UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    group_id    UUID NOT NULL REFERENCES groups(id) ON DELETE CASCADE,
+    user_id     UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    added_by    UUID NOT NULL REFERENCES users(id),
+    added_at    TIMESTAMPTZ DEFAULT NOW(),
+
+    UNIQUE(group_id, user_id)
+);
+
+CREATE INDEX IF NOT EXISTS idx_group_members_user ON group_members(user_id);
+CREATE INDEX IF NOT EXISTS idx_group_members_group ON group_members(group_id);
+```
+
+### 1.3 Resource Grants Table
+
+```sql
+-- =========================================
+-- RESOURCE GRANTS
+-- =========================================
+
+CREATE TABLE IF NOT EXISTS resource_grants (
+    id              UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    resource_type   VARCHAR(30) NOT NULL
+                    CHECK (resource_type IN ('persona', 'knowledge_base')),
+    resource_id     UUID NOT NULL,
+    grant_scope     VARCHAR(20) NOT NULL DEFAULT 'team_only'
+                    CHECK (grant_scope IN ('team_only', 'global', 'groups')),
+    granted_groups  UUID[] NOT NULL DEFAULT '{}',
+    created_by      UUID NOT NULL REFERENCES users(id),
+    created_at      TIMESTAMPTZ DEFAULT NOW(),
+    updated_at      TIMESTAMPTZ DEFAULT NOW(),
+
+    -- Only one grant row per resource
+    UNIQUE(resource_type, resource_id)
+);
+
+CREATE INDEX IF NOT EXISTS idx_resource_grants_resource
+    ON resource_grants(resource_type, resource_id);
+CREATE INDEX IF NOT EXISTS idx_resource_grants_groups
+    ON resource_grants USING gin(granted_groups);
+    -- GIN index for UUID[] containment queries (&&, @>)
+
+COMMENT ON TABLE resource_grants IS
+    'Controls cross-team access to resources (personas, KBs, future: projects).';
+COMMENT ON COLUMN resource_grants.grant_scope IS
+    'team_only: existing team scope behavior. global: all authenticated users. groups: specific group list.';
+COMMENT ON COLUMN resource_grants.granted_groups IS
+    'UUID array of group IDs. Only meaningful when grant_scope = groups.';
+```
+
+### 1.4 Triggers
+
+```sql
+-- Auto-update updated_at
+CREATE TRIGGER groups_updated_at
+    BEFORE UPDATE ON groups
+    FOR EACH ROW EXECUTE FUNCTION update_updated_at();
+
+CREATE TRIGGER resource_grants_updated_at
+    BEFORE UPDATE ON resource_grants
+    FOR EACH ROW EXECUTE FUNCTION update_updated_at();
+```
+
+### Design Decision: UUID[] vs Junction Table
+
+The roadmap specifies `granted_groups UUID[]` on `resource_grants`. This is
+the right call for this use case:
+
+- A resource has exactly one grant row (UNIQUE constraint).
+- The group list is always read/written as a unit (replace-all semantics).
+- Postgres `UUID[] && ARRAY[...]::uuid[]` with a GIN index is fast for
+  "does this resource grant overlap with the user's groups?" queries.
+- Avoids a many-to-many junction table that would complicate the common
+  path (checking access) for marginal normalization benefit.
+
+A junction table (`resource_grant_groups`) would be warranted if we needed
+per-group config on grants (e.g., read-only vs read-write per group). We
+don't — the grant is binary (access or no access). If that changes, we
+can migrate the array to a junction table later.
+
+---
+
+## 2. Models
+
+### 2.1 Group Models
+
+```go
+// ── Group Constants ────────────────────────
+
+const (
+    GroupScopeGlobal = "global"
+    GroupScopeTeam   = "team"
+)
+
+// ── Groups ─────────────────────────────────
+
+type Group struct {
+    ID          string    `json:"id" db:"id"`
+    Name        string    `json:"name" db:"name"`
+    Description string    `json:"description" db:"description"`
+    Scope       string    `json:"scope" db:"scope"`
+    TeamID      *string   `json:"team_id,omitempty" db:"team_id"`
+    CreatedBy   string    `json:"created_by" db:"created_by"`
+    CreatedAt   time.Time `json:"created_at" db:"created_at"`
+    UpdatedAt   time.Time `json:"updated_at" db:"updated_at"`
+
+    // Computed fields (not stored in groups table)
+    MemberCount int    `json:"member_count,omitempty"`
+    TeamName    string `json:"team_name,omitempty"`
+}
+
+type GroupPatch struct {
+    Name        *string `json:"name,omitempty"`
+    Description *string `json:"description,omitempty"`
+}
+
+type GroupMember struct {
+    ID          string `json:"id" db:"id"`
+    GroupID     string `json:"group_id" db:"group_id"`
+    UserID      string `json:"user_id" db:"user_id"`
+    AddedBy     string `json:"added_by" db:"added_by"`
+    AddedAt     string `json:"added_at" db:"added_at"`
+    // Joined from users table
+    Username    string `json:"username,omitempty"`
+    DisplayName string `json:"display_name,omitempty"`
+    Email       string `json:"email,omitempty"`
+}
+```
+
+### 2.2 Resource Grant Models
+
+```go
+// ── Resource Grant Constants ───────────────
+
+const (
+    ResourceTypePersona      = "persona"
+    ResourceTypeKnowledgeBase = "knowledge_base"
+    // Future: "project"
+
+    GrantScopeTeamOnly = "team_only"
+    GrantScopeGlobal   = "global"
+    GrantScopeGroups   = "groups"
+)
+
+// ResourceGrant controls cross-team access to a resource.
+type ResourceGrant struct {
+    ID            string    `json:"id" db:"id"`
+    ResourceType  string    `json:"resource_type" db:"resource_type"`
+    ResourceID    string    `json:"resource_id" db:"resource_id"`
+    GrantScope    string    `json:"grant_scope" db:"grant_scope"`
+    GrantedGroups []string  `json:"granted_groups" db:"granted_groups"` // UUID[]
+    CreatedBy     string    `json:"created_by" db:"created_by"`
+    CreatedAt     time.Time `json:"created_at" db:"created_at"`
+    UpdatedAt     time.Time `json:"updated_at" db:"updated_at"`
+}
+```
+
+---
+
+## 3. Store Interfaces
+
+### 3.1 GroupStore
+
+```go
+// =========================================
+// GROUP STORE
+// =========================================
+
+type GroupStore interface {
+    // CRUD
+    Create(ctx context.Context, g *models.Group) error
+    GetByID(ctx context.Context, id string) (*models.Group, error)
+    Update(ctx context.Context, id string, patch models.GroupPatch) error
+    Delete(ctx context.Context, id string) error
+
+    // Listing
+    ListAll(ctx context.Context) ([]models.Group, error)             // admin view
+    ListForTeam(ctx context.Context, teamID string) ([]models.Group, error)
+    ListForUser(ctx context.Context, userID string) ([]models.Group, error) // groups I'm in
+
+    // Members
+    AddMember(ctx context.Context, groupID, userID, addedBy string) error
+    RemoveMember(ctx context.Context, groupID, userID string) error
+    ListMembers(ctx context.Context, groupID string) ([]models.GroupMember, error)
+    IsMember(ctx context.Context, groupID, userID string) (bool, error)
+
+    // Bulk lookups (for access resolution)
+    GetUserGroupIDs(ctx context.Context, userID string) ([]string, error)
+}
+```
+
+### 3.2 ResourceGrantStore
+
+```go
+// =========================================
+// RESOURCE GRANT STORE
+// =========================================
+
+type ResourceGrantStore interface {
+    // Upsert: one grant row per resource (replace semantics)
+    Set(ctx context.Context, grant *models.ResourceGrant) error
+    Get(ctx context.Context, resourceType, resourceID string) (*models.ResourceGrant, error)
+    Delete(ctx context.Context, resourceType, resourceID string) error
+
+    // Access check: does user have group-based access to this resource?
+    UserHasGroupAccess(ctx context.Context, userID, resourceType, resourceID string) (bool, error)
+}
+```
+
+### 3.3 Wire into Stores Bundle
+
+```go
+type Stores struct {
+    // ... existing fields ...
+    Groups         GroupStore
+    ResourceGrants ResourceGrantStore
+}
+```
+
+---
+
+## 4. Access Resolution
+
+### 4.1 The Problem
+
+Today, access checks look like this (Persona example):
+
+```sql
+-- PersonaStore.ListForUser
+WHERE scope = 'global'
+   OR (scope = 'personal' AND created_by = $1)
+   OR (scope = 'team' AND owner_id IN (SELECT team_id FROM team_members WHERE user_id = $1))
+   OR (scope = 'personal' AND is_shared = true)
+```
+
+KB access follows the same pattern in `KnowledgeBaseStore.ListForUser` and
+the handler's `userCanAccess()` method.
+
+Groups add a fourth access path: "I'm in a group that has been granted
+access to this resource."
+
+### 4.2 Design: Parallel Check, Not Query Rewrite
+
+We could embed the group check into every `ListForUser` query. That would
+mean every listing query joins against `resource_grants` and `group_members`,
+adding complexity to every scope-aware query in the system.
+
+Instead: **keep existing scope queries as-is, add group-granted resources
+as a separate UNION.** This is cleaner, backward-compatible, and doesn't
+slow down the common path for users without group-based access.
+
+### 4.3 Updated Persona Listing
+
+```go
+// PersonaStore.ListForUser — updated
+func (s *PersonaStore) ListForUser(ctx context.Context, userID string) ([]models.Persona, error) {
+    rows, err := DB.QueryContext(ctx, fmt.Sprintf(`
+        -- Existing scope-based access (unchanged)
+        SELECT %s FROM personas WHERE is_active = true AND (
+            scope = 'global'
+            OR (scope = 'personal' AND created_by = $1)
+            OR (scope = 'team' AND owner_id IN (
+                SELECT team_id FROM team_members WHERE user_id = $1
+            ))
+            OR (scope = 'personal' AND is_shared = true)
+        )
+
+        UNION
+
+        -- Group-based access (new)
+        SELECT %s FROM personas p
+        WHERE p.is_active = true
+          AND p.id IN (
+            SELECT rg.resource_id FROM resource_grants rg
+            WHERE rg.resource_type = 'persona'
+              AND (
+                rg.grant_scope = 'global'
+                OR (rg.grant_scope = 'groups' AND rg.granted_groups && (
+                    SELECT ARRAY_AGG(gm.group_id) FROM group_members gm
+                    WHERE gm.user_id = $1
+                )::uuid[])
+              )
+          )
+
+        ORDER BY scope, name
+    `, personaCols, personaCols), userID)
+    // ...
+}
+```
+
+The `&&` operator is the Postgres array overlap operator — returns true if
+the two arrays share any element. The GIN index on `granted_groups` makes
+this efficient.
+
+### 4.4 Updated KB Listing
+
+Same pattern applied to `KnowledgeBaseStore.ListForUser`:
+
+```go
+func (s *KnowledgeBaseStore) ListForUser(ctx context.Context, userID string, teamIDs []string) ([]models.KnowledgeBase, error) {
+    // ... existing scope-based query ...
+
+    // Add UNION for group-granted KBs
+    q += `
+        UNION
+        SELECT id, name, description, scope, owner_id, team_id, embedding_config,
+            document_count, chunk_count, total_bytes, status, created_at, updated_at
+        FROM knowledge_bases kb
+        WHERE kb.id IN (
+            SELECT rg.resource_id FROM resource_grants rg
+            WHERE rg.resource_type = 'knowledge_base'
+              AND (
+                rg.grant_scope = 'global'
+                OR (rg.grant_scope = 'groups' AND rg.granted_groups && (
+                    SELECT ARRAY_AGG(gm.group_id) FROM group_members gm
+                    WHERE gm.user_id = $1
+                )::uuid[])
+              )
+        )`
+
+    q += ` ORDER BY name`
+    return queryKBs(ctx, q, args...)
+}
+```
+
+### 4.5 Updated UserCanAccess
+
+The KB handler's `userCanAccess()` method also needs updating:
+
+```go
+func (h *KnowledgeBaseHandler) userCanAccess(kb *models.KnowledgeBase, userID string, teamIDs []string) bool {
+    // Existing scope-based check (unchanged)
+    switch kb.Scope {
+    case "global":
+        return true
+    case "personal":
+        if kb.OwnerID != nil && *kb.OwnerID == userID {
+            return true
+        }
+    case "team":
+        if kb.TeamID != nil {
+            for _, tid := range teamIDs {
+                if tid == *kb.TeamID {
+                    return true
+                }
+            }
+        }
+    }
+
+    // New: check group-based grants
+    hasAccess, _ := h.stores.ResourceGrants.UserHasGroupAccess(
+        context.Background(), userID, models.ResourceTypeKnowledgeBase, kb.ID)
+    return hasAccess
+}
+```
+
+The `PersonaStore.UserCanAccess` method gets the same treatment.
+
+### 4.6 GetActiveKBIDs (Channel KB Access)
+
+The `GetActiveKBIDs` query (used by the completion handler to determine which
+KBs to search) also needs the group path:
+
+```sql
+-- Add to the WHERE clause:
+OR kb.id IN (
+    SELECT rg.resource_id FROM resource_grants rg
+    WHERE rg.resource_type = 'knowledge_base'
+      AND (
+        rg.grant_scope = 'global'
+        OR (rg.grant_scope = 'groups' AND rg.granted_groups && (
+            SELECT ARRAY_AGG(gm.group_id) FROM group_members gm
+            WHERE gm.user_id = $2
+        )::uuid[])
+      )
+)
+```
+
+### 4.7 Performance Note: User Group IDs Cache
+
+The `ARRAY_AGG(gm.group_id)` subquery appears in every access check. For
+hot paths (listing, access checks), we can pre-fetch the user's group IDs
+once per request and pass them through:
+
+```go
+// In middleware or handler setup:
+groupIDs, _ := stores.Groups.GetUserGroupIDs(ctx, userID)
+
+// Then in queries, pass as a parameter instead of subquery:
+// ... AND rg.granted_groups && $N::uuid[]
+```
+
+This trades a subquery for a pre-fetched array parameter. Worth doing in
+phase 2 if access checks show up in profiling. For v0.16.0, the subquery
+approach is simpler and correct.
+
+---
+
+## 5. Handlers
+
+### 5.1 GroupHandler
+
+```go
+type GroupHandler struct {
+    stores store.Stores
+}
+
+func NewGroupHandler(s store.Stores) *GroupHandler {
+    return &GroupHandler{stores: s}
+}
+```
+
+**Admin endpoints (global groups):**
+
+| Method | Path | Handler | Auth |
+|--------|------|---------|------|
+| GET | `/admin/groups` | ListAllGroups | admin |
+| POST | `/admin/groups` | CreateGlobalGroup | admin |
+| PUT | `/admin/groups/:id` | UpdateGroup | admin |
+| DELETE | `/admin/groups/:id` | DeleteGroup | admin |
+| GET | `/admin/groups/:id/members` | ListGroupMembers | admin |
+| POST | `/admin/groups/:id/members` | AddGroupMember | admin |
+| DELETE | `/admin/groups/:id/members/:userId` | RemoveGroupMember | admin |
+
+**Team endpoints (team-scoped groups):**
+
+| Method | Path | Handler | Auth |
+|--------|------|---------|------|
+| GET | `/teams/:teamId/groups` | ListTeamGroups | team member |
+| POST | `/teams/:teamId/groups` | CreateTeamGroup | team admin |
+| PUT | `/teams/:teamId/groups/:id` | UpdateTeamGroup | team admin |
+| DELETE | `/teams/:teamId/groups/:id` | DeleteTeamGroup | team admin |
+| GET | `/teams/:teamId/groups/:id/members` | ListTeamGroupMembers | team member |
+| POST | `/teams/:teamId/groups/:id/members` | AddTeamGroupMember | team admin |
+| DELETE | `/teams/:teamId/groups/:id/members/:userId` | RemoveTeamGroupMember | team admin |
+
+**User endpoint:**
+
+| Method | Path | Handler | Auth |
+|--------|------|---------|------|
+| GET | `/groups/mine` | MyGroups | authenticated |
+
+### 5.2 Resource Grant Endpoints
+
+Grant management is inline on the resource endpoints, not a separate handler.
+
+**On Personas:**
+
+| Method | Path | Handler | Auth |
+|--------|------|---------|------|
+| GET | `/presets/:id/grants` | GetPersonaGrants | owner or admin |
+| PUT | `/presets/:id/grants` | SetPersonaGrants | owner or admin |
+
+**On Knowledge Bases:**
+
+| Method | Path | Handler | Auth |
+|--------|------|---------|------|
+| GET | `/knowledge-bases/:id/grants` | GetKBGrants | owner or admin |
+| PUT | `/knowledge-bases/:id/grants` | SetKBGrants | owner or admin |
+
+**Request/response format:**
+
+```json
+// PUT /api/v1/presets/:id/grants
+{
+    "grant_scope": "groups",
+    "granted_groups": ["uuid-1", "uuid-2"]
+}
+
+// GET /api/v1/presets/:id/grants
+{
+    "grant_scope": "groups",
+    "granted_groups": [
+        { "id": "uuid-1", "name": "Engineering" },
+        { "id": "uuid-2", "name": "Design" }
+    ]
+}
+```
+
+The GET response enriches group UUIDs with names for display. The PUT
+accepts bare UUIDs.
+
+---
+
+## 6. Routes (main.go)
+
+```go
+// ── Groups ──────────────────────────────
+
+// User: my groups
+protected.GET("/groups/mine", groupH.MyGroups)
+
+// Team-scoped groups
+teamScoped.GET("/groups", groupH.ListTeamGroups)
+teamScoped.POST("/groups", groupH.CreateTeamGroup)       // RequireTeamAdmin
+teamScoped.PUT("/groups/:groupId", groupH.UpdateTeamGroup)   // RequireTeamAdmin
+teamScoped.DELETE("/groups/:groupId", groupH.DeleteTeamGroup) // RequireTeamAdmin
+teamScoped.GET("/groups/:groupId/members", groupH.ListTeamGroupMembers)
+teamScoped.POST("/groups/:groupId/members", groupH.AddTeamGroupMember)       // RequireTeamAdmin
+teamScoped.DELETE("/groups/:groupId/members/:userId", groupH.RemoveTeamGroupMember) // RequireTeamAdmin
+
+// Admin: global groups
+admin.GET("/groups", groupH.ListAllGroups)
+admin.POST("/groups", groupH.CreateGlobalGroup)
+admin.PUT("/groups/:id", groupH.UpdateGroup)
+admin.DELETE("/groups/:id", groupH.DeleteGroup)
+admin.GET("/groups/:id/members", groupH.ListGroupMembers)
+admin.POST("/groups/:id/members", groupH.AddGroupMember)
+admin.DELETE("/groups/:id/members/:userId", groupH.RemoveGroupMember)
+
+// ── Resource Grants ─────────────────────
+
+// Persona grants (add to existing preset routes)
+protected.GET("/presets/:id/grants", personaH.GetGrants)
+protected.PUT("/presets/:id/grants", personaH.SetGrants)
+
+// KB grants (add to existing KB routes)
+protected.GET("/knowledge-bases/:id/grants", kbH.GetGrants)
+protected.PUT("/knowledge-bases/:id/grants", kbH.SetGrants)
+```
+
+---
+
+## 7. Audit Logging
+
+All group and grant operations log to the existing audit system:
+
+| Action | Resource Type | Details |
+|--------|--------------|---------|
+| `group.create` | `group` | name, scope, team_id |
+| `group.update` | `group` | changed fields |
+| `group.delete` | `group` | name |
+| `group.member.add` | `group` | user_id |
+| `group.member.remove` | `group` | user_id |
+| `resource_grant.set` | `persona` / `knowledge_base` | grant_scope, group count |
+| `resource_grant.delete` | `persona` / `knowledge_base` | — |
+
+Uses the existing `AuditStore.Log` method — no new infrastructure.
+
+---
+
+## 8. Frontend
+
+### 8.1 Admin Panel: Groups Section
+
+New tab in the admin panel (alongside Users, Teams, Models, Settings, etc.):
+
+**Groups list view:**
+- Table: Name, Scope, Team (if team-scoped), Members count, Actions
+- "Create Group" button → modal with name, description, scope selector
+- Click row → member management (add/remove users, search by username)
+
+**Team admin panel:**
+- New "Groups" tab under team settings
+- Same list/CRUD pattern, scoped to team
+
+### 8.2 Grant Picker Component
+
+Reusable component for Persona and KB create/edit forms:
+
+```
+┌─ Access ──────────────────────────────────┐
+│  ○ Team Only (default)                     │
+│  ○ All Users                               │
+│  ○ Specific Groups                         │
+│    ┌────────────────────────────────────┐  │
+│    │ [x] Engineering                    │  │
+│    │ [x] Design                         │  │
+│    │ [ ] Marketing                      │  │
+│    │ [ ] Leadership                     │  │
+│    └────────────────────────────────────┘  │
+└────────────────────────────────────────────┘
+```
+
+- Only shown for team-scoped and global-scoped resources (personal resources
+  are always owner-only).
+- "Team Only" = existing behavior (no `resource_grants` row, or row with
+  `grant_scope = 'team_only'`).
+- "All Users" = `grant_scope = 'global'`.
+- "Specific Groups" = `grant_scope = 'groups'` + multi-select group picker.
+- Group list loaded from `/api/v1/groups/mine` (user's groups) for team
+  admins, `/api/v1/admin/groups` for system admins.
+
+### 8.3 User's Group Badge
+
+The model selector and KB list already show scope badges (`global`, `team`,
+`personal`). For group-granted resources, show a "group" badge to distinguish
+from team-native access.
+
+---
+
+## 9. Backward Compatibility
+
+### 9.1 No Breaking Changes
+
+- All existing scope-based queries remain valid.
+- Resources without a `resource_grants` row behave exactly as before.
+- The `resource_grants` table is opt-in: only populated when an admin or
+  team admin explicitly sets grants on a resource.
+- `persona_grants` (tool/KB/API grants ON a persona) is unrelated to
+  `resource_grants` (access grants TO a persona). Different concepts,
+  different tables. No rename needed.
+
+### 9.2 Migration Safety
+
+- New tables only (no ALTER on existing tables).
+- No data migration required.
+- Rollback: drop the three new tables.
+
+### 9.3 Naming Clarity
+
+To avoid confusion between the existing `persona_grants` table (which
+controls what tools/KBs a Persona has access TO) and the new
+`resource_grants` table (which controls which users have access TO the
+Persona):
+
+| Table | Purpose | Example |
+|-------|---------|---------|
+| `persona_grants` | What a Persona can do (tools, KBs, APIs) | "CodeBot can use calculator" |
+| `resource_grants` | Who can use a resource (users via groups) | "Engineering group can use CodeBot" |
+
+The naming is intentionally distinct. No rename of `persona_grants` is needed.
+
+---
+
+## 10. Implementation Phases
+
+### Phase 1: Groups Entity (backend)
+- [ ] Migration `010_groups.sql`
+- [ ] Models: `Group`, `GroupPatch`, `GroupMember`
+- [ ] Store: `GroupStore` interface + Postgres implementation
+- [ ] Handler: `GroupHandler` with admin + team admin + user endpoints
+- [ ] Routes: wire into `main.go`
+- [ ] Audit logging for group operations
+- [ ] Integration tests: CRUD, membership, scoping
+
+### Phase 2: Resource Grants (backend)
+- [ ] Models: `ResourceGrant` + constants
+- [ ] Store: `ResourceGrantStore` interface + Postgres implementation
+- [ ] Grant endpoints on PersonaHandler and KBHandler
+- [ ] Update `PersonaStore.ListForUser` with UNION for group access
+- [ ] Update `PersonaStore.UserCanAccess` with group check
+- [ ] Update `KnowledgeBaseStore.ListForUser` with UNION for group access
+- [ ] Update `KBHandler.userCanAccess` with group check
+- [ ] Update `KnowledgeBaseStore.GetActiveKBIDs` with group path
+- [ ] Audit logging for grant operations
+- [ ] Integration tests: grant CRUD, access resolution, cross-team visibility
+
+### Phase 3: Frontend
+- [ ] Admin panel: Groups section (CRUD, member management)
+- [ ] Team admin panel: Groups tab
+- [ ] Grant picker component (shared between Persona and KB forms)
+- [ ] `/groups/mine` endpoint for user's group list
+- [ ] "Group" scope badge on model selector / KB list
+- [ ] Update Persona create/edit form with grant picker
+- [ ] Update KB create/edit form with grant picker
+
+---
+
+## 11. Testing Plan
+
+### Integration Tests (extend `handlers/integration_test.go`)
+
+**Group lifecycle:**
+1. Admin creates global group → verify in list
+2. Admin adds users to group → verify membership
+3. Team admin creates team group → verify scoping (not visible to other teams)
+4. Remove member → verify no longer in group
+5. Delete group → verify CASCADE cleans up members
+
+**Resource grants:**
+1. Team admin creates a KB with `grant_scope = 'groups'`, grants to a group
+2. User in the group can see the KB in `ListForUser` → verify access
+3. User NOT in the group cannot see the KB → verify denied
+4. User in group can search the KB via `kb_search` tool → verify access
+5. Remove user from group → verify KB no longer visible
+6. Change grant from `groups` to `global` → verify all users can access
+7. Delete grant → verify KB reverts to team-only visibility
+
+**Backward compatibility:**
+1. Resources with no `resource_grants` row → same behavior as before
+2. Existing scope queries → unchanged results
+3. Personal resources → never grant-accessible (grant picker hidden)
+
+### Edge Cases
+- User belongs to 0 groups → `ARRAY_AGG` returns NULL → no match (safe)
+- Group with 0 members → grant exists but no one matches (correct)
+- Delete a group that's referenced in `granted_groups` → array still contains
+  the UUID but no `group_members` rows match → effectively revoked (correct).
+  Cleanup: periodic job or ON DELETE trigger to scrub stale UUIDs from arrays.
+  For v0.16.0, stale UUIDs are harmless (they just don't match anything).
+
+---
+
+## 12. Future Considerations
+
+### v0.17.0 — Persona-KB Binding
+Resource grants enable the access control layer for Persona-KB binding.
+When a Persona has bound KBs, the Persona's grants implicitly grant search
+access to those KBs. The `resource_grants` table already supports this —
+the Persona grant controls who can use the Persona, and Persona-KB binding
+controls which KBs are searchable through it.
+
+### v0.19.0 — Projects
+Projects will use the same `resource_grants` pattern:
+`resource_type = 'project'`. No schema changes needed.
+
+### v0.24.0 — Full RBAC
+OIDC claim → group mapping will auto-sync external IdP groups into the
+`groups` table. The infrastructure built here becomes the foundation for
+enterprise RBAC.
+
+### Stale Group UUID Cleanup
+When a group is deleted, its UUID may linger in `resource_grants.granted_groups`
+arrays. This is harmless (dead UUIDs never match any `group_members` rows)
+but untidy. Options for a future cleanup:
+- Trigger on `groups` DELETE that scrubs the UUID from all `granted_groups` arrays.
+- Periodic background job.
+- Cleanup on next grant SET (when the admin edits the grant).
+
+For v0.16.0, we'll add a note in the delete handler response if the group
+is referenced in any grants, warning the admin.
diff --git a/scripts/db-validate.sh b/scripts/db-validate.sh
index cc329ab..a1b4efe 100644
--- a/scripts/db-validate.sh
+++ b/scripts/db-validate.sh
@@ -1,10 +1,11 @@
 #!/bin/bash
 # ============================================
-# Chat Switchboard - Schema Validation (v0.9)
+# Chat Switchboard - Schema Validation (v0.16)
 # ============================================
 # Verifies the database schema is correct after
 # migration. Checks expected tables, key columns,
-# and constraints. Exits non-zero on any failure.
+# indexes, triggers, and confirms dropped artifacts.
+# Exits non-zero on any failure.
 #
 # Required env vars:
 #   PGHOST, PGPORT, PGUSER, PGPASSWORD, PGDATABASE
@@ -20,10 +21,12 @@ echo "Schema validation: ${PGDATABASE}"
 echo "━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━"
 
 ERRORS=0
+CHECKS=0
 
 # ── Helper: check table exists ───────────────
 check_table() {
     local table="$1"
+    CHECKS=$((CHECKS + 1))
     local exists
     exists=$(psql -tAc "SELECT 1 FROM information_schema.tables WHERE table_schema='public' AND table_name='${table}';")
     if [[ "${exists}" == "1" ]]; then
@@ -34,10 +37,25 @@ check_table() {
     fi
 }
 
+# ── Helper: check table does NOT exist ───────
+check_table_absent() {
+    local table="$1"
+    CHECKS=$((CHECKS + 1))
+    local exists
+    exists=$(psql -tAc "SELECT 1 FROM information_schema.tables WHERE table_schema='public' AND table_name='${table}';")
+    if [[ "${exists}" == "1" ]]; then
+        echo "  ✗ UNEXPECTED table: ${table} (should have been dropped)"
+        ERRORS=$((ERRORS + 1))
+    else
+        echo "  ✓ absent: ${table}"
+    fi
+}
+
 # ── Helper: check column exists ──────────────
 check_column() {
     local table="$1"
     local column="$2"
+    CHECKS=$((CHECKS + 1))
     local exists
     exists=$(psql -tAc "SELECT 1 FROM information_schema.columns WHERE table_schema='public' AND table_name='${table}' AND column_name='${column}';")
     if [[ "${exists}" == "1" ]]; then
@@ -48,9 +66,70 @@ check_column() {
     fi
 }
 
+# ── Helper: check column does NOT exist ──────
+check_column_absent() {
+    local table="$1"
+    local column="$2"
+    CHECKS=$((CHECKS + 1))
+    local exists
+    exists=$(psql -tAc "SELECT 1 FROM information_schema.columns WHERE table_schema='public' AND table_name='${table}' AND column_name='${column}';")
+    if [[ "${exists}" == "1" ]]; then
+        echo "  ✗ UNEXPECTED column: ${table}.${column} (should have been dropped)"
+        ERRORS=$((ERRORS + 1))
+    else
+        echo "  ✓ absent: ${table}.${column}"
+    fi
+}
+
+# ── Helper: check column type ────────────────
+check_column_type() {
+    local table="$1"
+    local column="$2"
+    local expected_type="$3"
+    CHECKS=$((CHECKS + 1))
+    local actual_type
+    actual_type=$(psql -tAc "SELECT data_type FROM information_schema.columns WHERE table_schema='public' AND table_name='${table}' AND column_name='${column}';")
+    if [[ "${actual_type}" == "${expected_type}" ]]; then
+        echo "  ✓ type: ${table}.${column} = ${expected_type}"
+    else
+        echo "  ✗ WRONG type: ${table}.${column} = ${actual_type} (expected ${expected_type})"
+        ERRORS=$((ERRORS + 1))
+    fi
+}
+
+# ── Helper: check index exists ───────────────
+check_index() {
+    local index="$1"
+    CHECKS=$((CHECKS + 1))
+    local exists
+    exists=$(psql -tAc "SELECT 1 FROM pg_indexes WHERE schemaname='public' AND indexname='${index}';")
+    if [[ "${exists}" == "1" ]]; then
+        echo "  ✓ index: ${index}"
+    else
+        echo "  ✗ MISSING index: ${index}"
+        ERRORS=$((ERRORS + 1))
+    fi
+}
+
+# ── Helper: check trigger exists ─────────────
+check_trigger() {
+    local trigger="$1"
+    local table="$2"
+    CHECKS=$((CHECKS + 1))
+    local exists
+    exists=$(psql -tAc "SELECT 1 FROM pg_trigger t JOIN pg_class c ON t.tgrelid = c.oid WHERE t.tgname='${trigger}' AND c.relname='${table}' AND NOT t.tgisinternal;")
+    if [[ "${exists}" == "1" ]]; then
+        echo "  ✓ trigger: ${trigger} on ${table}"
+    else
+        echo "  ✗ MISSING trigger: ${trigger} on ${table}"
+        ERRORS=$((ERRORS + 1))
+    fi
+}
+
 # ── Helper: check extension ──────────────────
 check_extension() {
     local ext="$1"
+    CHECKS=$((CHECKS + 1))
     local exists
     exists=$(psql -tAc "SELECT 1 FROM pg_extension WHERE extname='${ext}';")
     if [[ "${exists}" == "1" ]]; then
@@ -61,12 +140,17 @@ check_extension() {
     fi
 }
 
-# ── 1. Extensions ────────────────────────────
-echo ""
-echo "Extensions:"
-check_extension "pgcrypto"
+# ═══════════════════════════════════════════
+#  CHECKS
+# ═══════════════════════════════════════════
 
-# ── 2. Migration tracking ───────────────────
+# ── Extensions ────────────────────────────
+echo ""
+echo "PostgreSQL Extensions:"
+check_extension "pgcrypto"
+check_extension "vector"
+
+# ── Migration tracking ───────────────────
 echo ""
 echo "Migration tracking:"
 check_table "schema_migrations"
@@ -76,111 +160,177 @@ echo "  ✓ ${MIGRATION_COUNT} migrations applied"
 LATEST=$(psql -tAc "SELECT version FROM schema_migrations ORDER BY version DESC LIMIT 1;" 2>/dev/null || echo "none")
 echo "  ✓ latest: ${LATEST}"
 
-# ── 3. Core tables ──────────────────────────
+# ── Core tables ──────────────────────────
 echo ""
 echo "Core tables:"
 check_table "users"
-check_table "provider_configs"
-check_table "channels"
-check_table "messages"
+check_table "refresh_tokens"
 check_table "teams"
 check_table "team_members"
-check_table "refresh_tokens"
-check_table "global_settings"
-
-# ── 4. Users ────────────────────────────────
-echo ""
-echo "Users:"
-check_column "users" "id"
-check_column "users" "username"
-check_column "users" "email"
-check_column "users" "role"
-check_column "users" "is_active"
-check_column "users" "avatar_url"
-check_column "users" "display_name"
-check_column "users" "settings"
-
-# ── 5. Provider Configs (replaces api_configs) ─
-echo ""
-echo "Provider Configs:"
-check_column "provider_configs" "scope"
-check_column "provider_configs" "owner_id"
-check_column "provider_configs" "provider"
-check_column "provider_configs" "endpoint"
-check_column "provider_configs" "api_key_enc"
-check_column "provider_configs" "headers"
-check_column "provider_configs" "settings"
-check_column "provider_configs" "is_active"
-
-# ── 6. Model Catalog (replaces model_configs) ─
-echo ""
-echo "Model Catalog:"
+check_table "groups"
+check_table "group_members"
+check_table "provider_configs"
 check_table "model_catalog"
-check_column "model_catalog" "provider_config_id"
-check_column "model_catalog" "model_id"
-check_column "model_catalog" "display_name"
-check_column "model_catalog" "capabilities"
-check_column "model_catalog" "pricing"
-check_column "model_catalog" "visibility"
-
-# ── 7. Personas (replaces model_presets) ────
-echo ""
-echo "Personas:"
 check_table "personas"
-check_column "personas" "scope"
-check_column "personas" "owner_id"
-check_column "personas" "name"
-check_column "personas" "base_model_id"
-check_column "personas" "provider_config_id"
-check_column "personas" "system_prompt"
-check_column "personas" "created_by"
-
-# ── 8. Channels ─────────────────────────────
-echo ""
-echo "Channels:"
-check_column "channels" "user_id"
-check_column "channels" "type"
-check_column "channels" "provider_config_id"
-check_column "channels" "team_id"
-check_column "channels" "settings"
+check_table "persona_grants"
+check_table "resource_grants"
+check_table "platform_policies"
+check_table "global_settings"
+check_table "user_model_settings"
+check_table "channels"
+check_table "messages"
 check_table "channel_members"
 check_table "channel_models"
 check_table "channel_cursors"
+check_table "folders"
+check_table "notes"
+check_table "audit_log"
+check_table "usage_log"
+check_table "model_pricing"
+check_table "extensions"
+check_table "extension_user_settings"
+check_table "attachments"
+check_table "knowledge_bases"
+check_table "kb_documents"
+check_table "kb_chunks"
+check_table "channel_knowledge_bases"
 
-# ── 9. Messages ─────────────────────────────
+# ── Dropped tables (v0.16.0 cleanup) ────
 echo ""
-echo "Messages:"
-check_column "messages" "channel_id"
-check_column "messages" "role"
+echo "Dropped tables (v0.16.0 cleanup):"
+check_table_absent "projects"
+check_table_absent "project_channels"
+
+# ── Users (vault) ────────────────────────
+echo ""
+echo "Users (vault):"
+check_column "users" "encrypted_uek"
+check_column "users" "uek_salt"
+check_column "users" "uek_nonce"
+check_column "users" "vault_set"
+
+# ── Provider Configs (encryption) ────────
+echo ""
+echo "Provider Configs (encryption):"
+check_column "provider_configs" "api_key_enc"
+check_column_type "provider_configs" "api_key_enc" "bytea"
+check_column "provider_configs" "key_nonce"
+check_column_type "provider_configs" "key_nonce" "bytea"
+check_column "provider_configs" "key_scope"
+check_column_absent "provider_configs" "api_key_plain"
+
+# ── Model Catalog ────────────────────────
+echo ""
+echo "Model Catalog:"
+check_column "model_catalog" "model_type"
+check_column "model_catalog" "visibility"
+check_column "model_catalog" "capabilities"
+
+# ── Groups (v0.16.0) ────────────────────
+echo ""
+echo "Groups (v0.16.0):"
+check_column "groups" "name"
+check_column "groups" "scope"
+check_column "groups" "team_id"
+check_column "groups" "created_by"
+check_column "group_members" "group_id"
+check_column "group_members" "user_id"
+check_column "group_members" "added_by"
+check_index "idx_group_members_user"
+check_index "idx_group_members_group"
+check_index "idx_groups_name_scope"
+
+# ── Resource Grants (v0.16.0) ───────────
+echo ""
+echo "Resource Grants (v0.16.0):"
+check_column "resource_grants" "resource_type"
+check_column "resource_grants" "resource_id"
+check_column "resource_grants" "grant_scope"
+check_column "resource_grants" "granted_groups"
+check_column "resource_grants" "created_by"
+check_index "idx_resource_grants_resource"
+check_index "idx_resource_grants_groups"
+
+# ── Personas ─────────────────────────────
+echo ""
+echo "Personas:"
+check_column "personas" "scope"
+check_column "personas" "owner_id"
+check_column "personas" "base_model_id"
+check_column "personas" "thinking_budget"
+check_column "personas" "is_shared"
+
+# ── Channels & Messages ──────────────────
+echo ""
+echo "Channels & Messages:"
+check_column "channels" "settings"
+check_column "channels" "folder_id"
+check_column "channels" "team_id"
 check_column "messages" "parent_id"
 check_column "messages" "sibling_index"
-check_column "messages" "deleted_at"
-check_column "messages" "participant_type"
+check_column "messages" "tool_calls"
+check_column "messages" "metadata"
 
-# ── 10. Organization ────────────────────────
+# ── Notes ────────────────────────────────
 echo ""
-echo "Organization:"
-check_table "folders"
-check_table "projects"
-check_table "notes"
+echo "Notes:"
 check_column "notes" "search_vector"
+check_column "notes" "embedding"
+check_column "notes" "team_id"
+check_index "idx_notes_search"
 
-# ── 11. User Model Settings ────────────────
+# ── Extensions ───────────────────────────
 echo ""
-echo "User Model Settings:"
-check_table "user_model_settings"
-check_column "user_model_settings" "user_id"
-check_column "user_model_settings" "model_id"
-check_column "user_model_settings" "hidden"
-check_column "user_model_settings" "sort_order"
+echo "Extensions:"
+check_column "extensions" "ext_id"
+check_column "extensions" "tier"
+check_column "extensions" "manifest"
+check_column "extensions" "is_system"
+check_column "extensions" "scope"
 
-# ── 12. Audit Log ───────────────────────────
+# ── Attachments ──────────────────────────
 echo ""
-echo "Audit Log:"
-check_table "audit_log"
-check_column "audit_log" "actor_id"
-check_column "audit_log" "action"
-check_column "audit_log" "resource_type"
+echo "Attachments:"
+check_column "attachments" "channel_id"
+check_column "attachments" "storage_key"
+check_column "attachments" "extracted_text"
+check_index "idx_attachments_channel"
+check_index "idx_attachments_orphan"
+
+# ── Knowledge Bases ──────────────────────
+echo ""
+echo "Knowledge Bases:"
+check_column "knowledge_bases" "scope"
+check_column "knowledge_bases" "embedding_config"
+check_column "knowledge_bases" "document_count"
+check_table "kb_documents"
+check_table "kb_chunks"
+check_column "kb_chunks" "embedding"
+check_table "channel_knowledge_bases"
+
+# ── Usage & Pricing ──────────────────────
+echo ""
+echo "Usage & Pricing:"
+check_column "usage_log" "provider_scope"
+check_column "usage_log" "role"
+check_column "usage_log" "cache_creation_tokens"
+check_column "model_pricing" "cache_create_per_m"
+
+# ── Key triggers ─────────────────────────
+echo ""
+echo "Key triggers:"
+check_trigger "users_updated_at" "users"
+check_trigger "channels_updated_at" "channels"
+check_trigger "personas_updated_at" "personas"
+check_trigger "groups_updated_at" "groups"
+check_trigger "resource_grants_updated_at" "resource_grants"
+check_trigger "notes_search_update" "notes"
+
+# ── CI Username Indexes ──────────────────
+echo ""
+echo "CI Username Indexes:"
+check_index "users_username_ci"
+check_index "users_email_ci"
 
 # ═══════════════════════════════════════════
 # ADD NEW MIGRATION CHECKS ABOVE THIS LINE
@@ -190,11 +340,11 @@ check_column "audit_log" "resource_type"
 echo ""
 echo "━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━"
 if [[ ${ERRORS} -eq 0 ]]; then
-    echo "✅ Schema validation passed (${MIGRATION_COUNT} migrations)"
+    echo "✅ Schema validation passed: ${CHECKS}/${CHECKS} checks OK"
     echo "━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━"
     exit 0
 else
-    echo "❌ Schema validation FAILED: ${ERRORS} errors"
+    echo "❌ Schema validation FAILED: ${ERRORS}/${CHECKS} checks failed"
     echo "━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━"
     exit 1
 fi
diff --git a/server/database/migrations/001_v09_schema.sql b/server/database/migrations/001_v016_schema.sql
similarity index 57%
rename from server/database/migrations/001_v09_schema.sql
rename to server/database/migrations/001_v016_schema.sql
index 564caff..07a3ec4 100644
--- a/server/database/migrations/001_v09_schema.sql
+++ b/server/database/migrations/001_v016_schema.sql
@@ -1,12 +1,22 @@
 -- ==========================================
--- Chat Switchboard — v0.9.0 Consolidated Schema
+-- Chat Switchboard — v0.16.0 Consolidated Schema
 -- ==========================================
--- Clean-slate schema. Replaces all 001–021 migrations.
+-- Clean-slate schema. Replaces all 001–009 migrations.
 -- Drop DB and re-create before applying.
 --
+-- Changes from v0.15.1 (9-file) schema:
+--   • Folded all incremental migrations into base CREATEs
+--   • Dropped api_key_plain (vault backfill complete)
+--   • Dropped projects, project_channels (unused, v0.19.0 redesigns)
+--   • Dropped 'moderator' from users.role CHECK (dead code)
+--   • CI usernames from the start (LOWER() unique indexes)
+--   • Added: groups, group_members, resource_grants (v0.16.0)
+--   • Added: pgvector extension declaration
+--
 -- Design principles:
 --   • Explicit scope enums over nullable column tri-states
 --   • Personas as trust boundaries with extensible grants
+--   • Groups as pure access-control lists (decouple from teams)
 --   • Secure by default (models hidden until admin enables)
 --   • Only tables with active handlers — no placeholder tables
 -- ==========================================
@@ -14,6 +24,23 @@
 -- ── Extensions ──────────────────────────────
 
 CREATE EXTENSION IF NOT EXISTS "pgcrypto";     -- gen_random_uuid()
+CREATE EXTENSION IF NOT EXISTS "vector";       -- pgvector (KB embeddings)
+
+-- ── Upgrade-path cleanup ───────────────────
+-- These objects existed in the 001–009 migration chain but were removed
+-- in the v0.16.0 consolidation. Safe no-ops on fresh installs.
+
+DROP TABLE IF EXISTS project_channels CASCADE;
+DROP TABLE IF EXISTS projects CASCADE;
+
+DO $$ BEGIN
+    IF EXISTS (
+        SELECT 1 FROM information_schema.columns
+        WHERE table_name = 'provider_configs' AND column_name = 'api_key_plain'
+    ) THEN
+        ALTER TABLE provider_configs DROP COLUMN api_key_plain;
+    END IF;
+END $$;
 
 -- ── Utility: auto-update updated_at ─────────
 
@@ -32,26 +59,43 @@ $$ LANGUAGE plpgsql;
 
 CREATE TABLE IF NOT EXISTS users (
     id              UUID PRIMARY KEY DEFAULT gen_random_uuid(),
-    username        VARCHAR(50) UNIQUE NOT NULL,
-    email           VARCHAR(255) UNIQUE NOT NULL,
+    username        VARCHAR(50) NOT NULL,
+    email           VARCHAR(255) NOT NULL,
     password_hash   TEXT NOT NULL,
     display_name    VARCHAR(100),
     avatar_url      TEXT,
     role            VARCHAR(20) DEFAULT 'user'
-                    CHECK (role IN ('user', 'admin', 'moderator')),
+                    CHECK (role IN ('user', 'admin')),
     is_active       BOOLEAN DEFAULT true,
     settings        JSONB DEFAULT '{}'::jsonb,
+
+    -- Vault: per-user encryption key (UEK) for BYOK API keys
+    encrypted_uek   BYTEA,
+    uek_salt        BYTEA,
+    uek_nonce       BYTEA,
+    vault_set       BOOLEAN NOT NULL DEFAULT false,
+
     created_at      TIMESTAMPTZ DEFAULT NOW(),
     updated_at      TIMESTAMPTZ DEFAULT NOW(),
     last_login_at   TIMESTAMPTZ
 );
 
+-- Case-insensitive unique indexes (no bare UNIQUE constraint)
+CREATE UNIQUE INDEX IF NOT EXISTS users_username_ci ON users (LOWER(username));
+CREATE UNIQUE INDEX IF NOT EXISTS users_email_ci ON users (LOWER(email));
+
 CREATE INDEX IF NOT EXISTS idx_users_username ON users(username);
 CREATE INDEX IF NOT EXISTS idx_users_email ON users(email);
+
 DROP TRIGGER IF EXISTS users_updated_at ON users;
 CREATE TRIGGER users_updated_at BEFORE UPDATE ON users
     FOR EACH ROW EXECUTE FUNCTION update_updated_at();
 
+COMMENT ON COLUMN users.encrypted_uek IS 'UEK encrypted with Argon2id(password)-derived key';
+COMMENT ON COLUMN users.uek_salt      IS 'Argon2id salt for UEK derivation';
+COMMENT ON COLUMN users.uek_nonce     IS 'AES-GCM nonce for UEK wrapping';
+COMMENT ON COLUMN users.vault_set     IS 'true once UEK has been generated and wrapped';
+
 
 -- =========================================
 -- 2. AUTH
@@ -107,9 +151,59 @@ CREATE INDEX IF NOT EXISTS idx_team_members_user ON team_members(user_id);
 
 
 -- =========================================
--- 4. PROVIDER CONFIGS (replaces api_configs)
+-- 4. GROUPS (v0.16.0)
+-- =========================================
+-- Pure access-control lists. Decouple resource visibility from team membership.
+-- Teams = organizational structure. Roles = vertical permissions.
+-- Groups = who can access what (cross-cutting).
+
+CREATE TABLE IF NOT EXISTS groups (
+    id          UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    name        VARCHAR(100) NOT NULL,
+    description TEXT NOT NULL DEFAULT '',
+    scope       VARCHAR(20) NOT NULL DEFAULT 'global'
+                CHECK (scope IN ('global', 'team')),
+    team_id     UUID REFERENCES teams(id) ON DELETE CASCADE,
+    created_by  UUID NOT NULL REFERENCES users(id),
+    created_at  TIMESTAMPTZ DEFAULT NOW(),
+    updated_at  TIMESTAMPTZ DEFAULT NOW(),
+
+    -- Global groups: team_id must be NULL
+    -- Team groups: team_id must be set
+    CONSTRAINT groups_scope_team CHECK (
+        (scope = 'global' AND team_id IS NULL) OR
+        (scope = 'team' AND team_id IS NOT NULL)
+    )
+);
+
+-- Unique name within scope (global names globally unique,
+-- team names unique within team)
+CREATE UNIQUE INDEX IF NOT EXISTS idx_groups_name_scope
+    ON groups(name, COALESCE(team_id, '00000000-0000-0000-0000-000000000000'));
+
+DROP TRIGGER IF EXISTS groups_updated_at ON groups;
+CREATE TRIGGER groups_updated_at BEFORE UPDATE ON groups
+    FOR EACH ROW EXECUTE FUNCTION update_updated_at();
+
+COMMENT ON TABLE groups IS 'Access-control groups. Decouple resource visibility from team membership.';
+COMMENT ON COLUMN groups.scope IS 'global: admin-managed, can span teams. team: team-admin-managed, team-internal.';
+
+CREATE TABLE IF NOT EXISTS group_members (
+    id          UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    group_id    UUID NOT NULL REFERENCES groups(id) ON DELETE CASCADE,
+    user_id     UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    added_by    UUID NOT NULL REFERENCES users(id),
+    added_at    TIMESTAMPTZ DEFAULT NOW(),
+    UNIQUE(group_id, user_id)
+);
+
+CREATE INDEX IF NOT EXISTS idx_group_members_group ON group_members(group_id);
+CREATE INDEX IF NOT EXISTS idx_group_members_user ON group_members(user_id);
+
+
+-- =========================================
+-- 5. PROVIDER CONFIGS
 -- =========================================
--- Explicit scope enum replaces nullable column tri-state.
 -- scope='global': admin-managed, visible to all users (owner_id IS NULL)
 -- scope='team':   team admin-managed (owner_id = teams.id)
 -- scope='personal': user's own keys (owner_id = users.id)
@@ -122,7 +216,12 @@ CREATE TABLE IF NOT EXISTS provider_configs (
     name            VARCHAR(100) NOT NULL,
     provider        VARCHAR(50) NOT NULL,
     endpoint        TEXT NOT NULL,
-    api_key_enc     TEXT,
+
+    -- Encrypted API key (AES-256-GCM)
+    api_key_enc     BYTEA,
+    key_nonce       BYTEA,
+    key_scope       TEXT NOT NULL DEFAULT 'global',
+
     model_default   VARCHAR(100),
     config          JSONB DEFAULT '{}'::jsonb,
     headers         JSONB DEFAULT '{}'::jsonb,
@@ -142,22 +241,26 @@ CREATE TRIGGER provider_configs_updated_at BEFORE UPDATE ON provider_configs
 
 COMMENT ON COLUMN provider_configs.scope IS 'global=admin-managed, team=team-scoped, personal=user BYOK';
 COMMENT ON COLUMN provider_configs.owner_id IS 'NULL for global; teams.id for team scope; users.id for personal scope';
+COMMENT ON COLUMN provider_configs.api_key_enc IS 'AES-256-GCM encrypted API key (BYTEA)';
+COMMENT ON COLUMN provider_configs.key_nonce IS 'AES-GCM nonce for api_key_enc';
+COMMENT ON COLUMN provider_configs.key_scope IS 'Encryption tier: global/team use env key, personal uses UEK';
 COMMENT ON COLUMN provider_configs.headers IS 'Custom HTTP headers (e.g. OpenRouter HTTP-Referer)';
 COMMENT ON COLUMN provider_configs.settings IS 'Provider-specific params (e.g. Venice web_search, OpenRouter route)';
 COMMENT ON COLUMN provider_configs.is_private IS 'Data stays on-prem (local/self-hosted provider)';
 
 
 -- =========================================
--- 5. MODEL CATALOG (replaces model_configs)
+-- 6. MODEL CATALOG
 -- =========================================
 -- Intrinsic capabilities for models the system knows about.
--- Hidden by default — admin must enable.
+-- Disabled by default — admin must enable.
 
 CREATE TABLE IF NOT EXISTS model_catalog (
     id                  UUID PRIMARY KEY DEFAULT gen_random_uuid(),
     provider_config_id  UUID NOT NULL REFERENCES provider_configs(id) ON DELETE CASCADE,
     model_id            TEXT NOT NULL,
     display_name        TEXT,
+    model_type          VARCHAR(20) DEFAULT 'chat',
     capabilities        JSONB NOT NULL DEFAULT '{}',
     pricing             JSONB,
     visibility          VARCHAR(10) DEFAULT 'disabled'
@@ -170,28 +273,18 @@ CREATE TABLE IF NOT EXISTS model_catalog (
 
 CREATE INDEX IF NOT EXISTS idx_model_catalog_provider ON model_catalog(provider_config_id);
 CREATE INDEX IF NOT EXISTS idx_model_catalog_enabled ON model_catalog(visibility) WHERE visibility = 'enabled';
-
--- Fix CHECK constraint and default for existing databases (idempotent)
-DO $$ BEGIN
-    ALTER TABLE model_catalog DROP CONSTRAINT IF EXISTS model_catalog_visibility_check;
-    -- Remap old values before adding new constraint
-    UPDATE model_catalog SET visibility = 'enabled' WHERE visibility = 'visible';
-    UPDATE model_catalog SET visibility = 'disabled' WHERE visibility = 'hidden';
-    ALTER TABLE model_catalog ADD CONSTRAINT model_catalog_visibility_check
-        CHECK (visibility IN ('enabled', 'disabled', 'team'));
-    ALTER TABLE model_catalog ALTER COLUMN visibility SET DEFAULT 'disabled';
-EXCEPTION WHEN OTHERS THEN NULL;
-END $$;
+CREATE INDEX IF NOT EXISTS idx_model_catalog_type ON model_catalog(model_type);
 DROP TRIGGER IF EXISTS model_catalog_updated_at ON model_catalog;
 CREATE TRIGGER model_catalog_updated_at BEFORE UPDATE ON model_catalog
     FOR EACH ROW EXECUTE FUNCTION update_updated_at();
 
-COMMENT ON COLUMN model_catalog.visibility IS 'hidden by default — admin must enable for global models';
+COMMENT ON COLUMN model_catalog.visibility IS 'disabled by default — admin must enable for global models';
+COMMENT ON COLUMN model_catalog.model_type IS 'chat, embedding, image — from provider API sync';
 COMMENT ON COLUMN model_catalog.capabilities IS 'Intrinsic: {"streaming","tool_calling","vision","thinking","reasoning","code_optimized","web_search","max_context","max_output_tokens"}';
 
 
 -- =========================================
--- 6. PERSONAS (replaces model_presets)
+-- 7. PERSONAS
 -- =========================================
 
 CREATE TABLE IF NOT EXISTS personas (
@@ -239,8 +332,10 @@ COMMENT ON COLUMN personas.is_shared IS 'Personal Personas shared with others (r
 
 
 -- =========================================
--- 7. PERSONA GRANTS (extensible resource binding)
+-- 8. PERSONA GRANTS (what a Persona can do)
 -- =========================================
+-- Controls tools, KBs, and API endpoints that a Persona has access TO.
+-- NOT to be confused with resource_grants (who can USE a resource).
 
 CREATE TABLE IF NOT EXISTS persona_grants (
     id              UUID PRIMARY KEY DEFAULT gen_random_uuid(),
@@ -255,13 +350,53 @@ CREATE TABLE IF NOT EXISTS persona_grants (
 CREATE INDEX IF NOT EXISTS idx_persona_grants_persona ON persona_grants(persona_id);
 CREATE INDEX IF NOT EXISTS idx_persona_grants_type ON persona_grants(grant_type);
 
-COMMENT ON COLUMN persona_grants.grant_type IS 'Extensible: tool, knowledge_base (future), api_endpoint (future)';
+COMMENT ON TABLE persona_grants IS 'What a Persona can do: tools it can call, KBs it can search, etc.';
+COMMENT ON COLUMN persona_grants.grant_type IS 'Extensible: tool, knowledge_base, api_endpoint';
 COMMENT ON COLUMN persona_grants.grant_ref IS 'tool: function name. knowledge_base: UUID. api_endpoint: identifier.';
 COMMENT ON COLUMN persona_grants.config IS 'Type-specific config, e.g. {"read_only": true} for KB grants';
 
 
 -- =========================================
--- 8. PLATFORM POLICIES (replaces scattered global_settings checks)
+-- 9. RESOURCE GRANTS (v0.16.0 — who can USE a resource)
+-- =========================================
+-- Controls which users (via groups) can access a resource.
+-- NOT to be confused with persona_grants (what a Persona can do).
+--
+-- persona_grants:   "CodeBot can use calculator"      (Persona → tool)
+-- resource_grants:  "Engineering can use CodeBot"      (group → Persona)
+
+CREATE TABLE IF NOT EXISTS resource_grants (
+    id              UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    resource_type   VARCHAR(30) NOT NULL
+                    CHECK (resource_type IN ('persona', 'knowledge_base')),
+    resource_id     UUID NOT NULL,
+    grant_scope     VARCHAR(20) NOT NULL DEFAULT 'team_only'
+                    CHECK (grant_scope IN ('team_only', 'global', 'groups')),
+    granted_groups  UUID[] NOT NULL DEFAULT '{}',
+    created_by      UUID NOT NULL REFERENCES users(id),
+    created_at      TIMESTAMPTZ DEFAULT NOW(),
+    updated_at      TIMESTAMPTZ DEFAULT NOW(),
+
+    -- One grant row per resource
+    UNIQUE(resource_type, resource_id)
+);
+
+CREATE INDEX IF NOT EXISTS idx_resource_grants_resource
+    ON resource_grants(resource_type, resource_id);
+CREATE INDEX IF NOT EXISTS idx_resource_grants_groups
+    ON resource_grants USING gin(granted_groups);
+
+DROP TRIGGER IF EXISTS resource_grants_updated_at ON resource_grants;
+CREATE TRIGGER resource_grants_updated_at BEFORE UPDATE ON resource_grants
+    FOR EACH ROW EXECUTE FUNCTION update_updated_at();
+
+COMMENT ON TABLE resource_grants IS 'Who can USE a resource (personas, KBs). Cross-team access via groups.';
+COMMENT ON COLUMN resource_grants.grant_scope IS 'team_only: existing team behavior. global: all users. groups: specific group list.';
+COMMENT ON COLUMN resource_grants.granted_groups IS 'UUID array of group IDs. Only meaningful when grant_scope = groups.';
+
+
+-- =========================================
+-- 10. PLATFORM POLICIES
 -- =========================================
 
 CREATE TABLE IF NOT EXISTS platform_policies (
@@ -285,10 +420,8 @@ COMMENT ON TABLE platform_policies IS 'Global admin switches controlling platfor
 
 
 -- =========================================
--- 9. GLOBAL SETTINGS (non-policy config)
+-- 11. GLOBAL SETTINGS (non-policy config)
 -- =========================================
--- Retained for banner config, site branding, etc.
--- Policy-like keys move to platform_policies.
 
 CREATE TABLE IF NOT EXISTS global_settings (
     key         VARCHAR(100) PRIMARY KEY,
@@ -297,7 +430,6 @@ CREATE TABLE IF NOT EXISTS global_settings (
     updated_by  UUID REFERENCES users(id)
 );
 
--- Seed defaults
 INSERT INTO global_settings (key, value) VALUES
     ('registration', '{"enabled": true}'::jsonb),
     ('site', '{"name": "Chat Switchboard", "tagline": "Multi-Model AI Chat"}'::jsonb),
@@ -315,12 +447,17 @@ INSERT INTO global_settings (key, value) VALUES
         "production":   { "text": "PRODUCTION",    "bg": "#c8102e", "fg": "#ffffff" },
         "training":     { "text": "TRAINING",      "bg": "#ff8c00", "fg": "#000000" },
         "demo":         { "text": "DEMO",          "bg": "#fce83a", "fg": "#000000" }
+    }'::jsonb),
+    ('model_roles', '{
+        "utility":    { "primary": null, "fallback": null },
+        "embedding":  { "primary": null, "fallback": null },
+        "generation": { "primary": null, "fallback": null }
     }'::jsonb)
 ON CONFLICT (key) DO NOTHING;
 
 
 -- =========================================
--- 10. USER MODEL SETTINGS (replaces user_model_preferences)
+-- 12. USER MODEL SETTINGS
 -- =========================================
 
 CREATE TABLE IF NOT EXISTS user_model_settings (
@@ -343,7 +480,7 @@ CREATE TRIGGER user_model_settings_updated_at BEFORE UPDATE ON user_model_settin
 
 
 -- =========================================
--- 11. CHANNELS (unified chats)
+-- 13. CHANNELS
 -- =========================================
 
 CREATE TABLE IF NOT EXISTS channels (
@@ -358,8 +495,8 @@ CREATE TABLE IF NOT EXISTS channels (
     provider_config_id UUID REFERENCES provider_configs(id) ON DELETE SET NULL,
     is_archived     BOOLEAN DEFAULT false,
     is_pinned       BOOLEAN DEFAULT false,
-    folder_id       UUID,   -- FK added after folders table
-    folder          TEXT,   -- backward compat: simple text folder name
+    folder_id       UUID,   -- FK added after folders table created
+    folder          TEXT,   -- simple text folder name (frontend-managed)
     team_id         UUID REFERENCES teams(id) ON DELETE SET NULL,
     settings        JSONB DEFAULT '{}'::jsonb,
     tags            TEXT[],
@@ -380,7 +517,7 @@ COMMENT ON COLUMN channels.type IS 'direct=1:1 AI chat, group=multi-model, chann
 
 
 -- =========================================
--- 12. MESSAGES (with tree/forking support)
+-- 14. MESSAGES (with tree/forking support)
 -- =========================================
 
 CREATE TABLE IF NOT EXISTS messages (
@@ -415,7 +552,7 @@ COMMENT ON COLUMN messages.participant_id IS 'user UUID or model identifier stri
 
 
 -- =========================================
--- 13. CHANNEL MEMBERS & MODELS
+-- 15. CHANNEL MEMBERS & MODELS
 -- =========================================
 
 CREATE TABLE IF NOT EXISTS channel_members (
@@ -448,7 +585,7 @@ CREATE INDEX IF NOT EXISTS idx_channel_models_channel ON channel_models(channel_
 
 
 -- =========================================
--- 14. CHANNEL CURSORS (forking navigation)
+-- 16. CHANNEL CURSORS (forking navigation)
 -- =========================================
 
 CREATE TABLE IF NOT EXISTS channel_cursors (
@@ -465,8 +602,9 @@ CREATE INDEX IF NOT EXISTS idx_channel_cursors_user ON channel_cursors(user_id);
 
 
 -- =========================================
--- 15. FOLDERS & PROJECTS
+-- 17. FOLDERS
 -- =========================================
+-- Channel folders. Note: projects table deferred to v0.19.0.
 
 CREATE TABLE IF NOT EXISTS folders (
     id              UUID PRIMARY KEY DEFAULT gen_random_uuid(),
@@ -485,41 +623,20 @@ DROP TRIGGER IF EXISTS folders_updated_at ON folders;
 CREATE TRIGGER folders_updated_at BEFORE UPDATE ON folders
     FOR EACH ROW EXECUTE FUNCTION update_updated_at();
 
--- Now add the FK from channels
+-- Deferred FK: channels.folder_id → folders.id
 DO $$ BEGIN
-    ALTER TABLE channels ADD CONSTRAINT fk_channels_folder
-        FOREIGN KEY (folder_id) REFERENCES folders(id) ON DELETE SET NULL;
-EXCEPTION WHEN duplicate_object THEN NULL;
+    IF NOT EXISTS (
+        SELECT 1 FROM pg_constraint WHERE conname = 'fk_channels_folder'
+    ) THEN
+        ALTER TABLE channels ADD CONSTRAINT fk_channels_folder
+            FOREIGN KEY (folder_id) REFERENCES folders(id) ON DELETE SET NULL;
+    END IF;
 END $$;
 CREATE INDEX IF NOT EXISTS idx_channels_folder ON channels(folder_id) WHERE folder_id IS NOT NULL;
 
-CREATE TABLE IF NOT EXISTS projects (
-    id              UUID PRIMARY KEY DEFAULT gen_random_uuid(),
-    user_id         UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
-    name            VARCHAR(200) NOT NULL,
-    description     TEXT,
-    color           VARCHAR(7),
-    created_at      TIMESTAMPTZ DEFAULT NOW(),
-    updated_at      TIMESTAMPTZ DEFAULT NOW()
-);
-
-CREATE INDEX IF NOT EXISTS idx_projects_user ON projects(user_id);
-DROP TRIGGER IF EXISTS projects_updated_at ON projects;
-CREATE TRIGGER projects_updated_at BEFORE UPDATE ON projects
-    FOR EACH ROW EXECUTE FUNCTION update_updated_at();
-
-CREATE TABLE IF NOT EXISTS project_channels (
-    project_id  UUID NOT NULL REFERENCES projects(id) ON DELETE CASCADE,
-    channel_id  UUID NOT NULL REFERENCES channels(id) ON DELETE CASCADE,
-    added_at    TIMESTAMPTZ DEFAULT NOW(),
-    PRIMARY KEY (project_id, channel_id)
-);
-
-CREATE INDEX IF NOT EXISTS idx_project_channels_channel ON project_channels(channel_id);
-
 
 -- =========================================
--- 16. NOTES
+-- 18. NOTES
 -- =========================================
 
 CREATE TABLE IF NOT EXISTS notes (
@@ -533,6 +650,7 @@ CREATE TABLE IF NOT EXISTS notes (
     source_channel_id   UUID REFERENCES channels(id) ON DELETE SET NULL,
     team_id             UUID REFERENCES teams(id) ON DELETE SET NULL,
     search_vector       TSVECTOR,
+    embedding           VECTOR(3072),
     created_at          TIMESTAMPTZ DEFAULT NOW(),
     updated_at          TIMESTAMPTZ DEFAULT NOW()
 );
@@ -562,7 +680,7 @@ CREATE TRIGGER notes_search_update
 
 
 -- =========================================
--- 17. AUDIT LOG
+-- 19. AUDIT LOG
 -- =========================================
 
 CREATE TABLE IF NOT EXISTS audit_log (
@@ -583,3 +701,184 @@ CREATE INDEX IF NOT EXISTS idx_audit_log_resource ON audit_log(resource_type, re
 CREATE INDEX IF NOT EXISTS idx_audit_log_action ON audit_log(action);
 
 COMMENT ON TABLE audit_log IS 'Immutable audit trail of all mutating operations';
+
+
+-- =========================================
+-- 20. USAGE TRACKING
+-- =========================================
+
+CREATE TABLE IF NOT EXISTS usage_log (
+    id                    UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    channel_id            UUID REFERENCES channels(id) ON DELETE SET NULL,
+    user_id               UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    provider_config_id    UUID REFERENCES provider_configs(id) ON DELETE SET NULL,
+    provider_scope        TEXT NOT NULL DEFAULT 'global',
+    model_id              TEXT NOT NULL,
+    role                  TEXT,  -- NULL = user chat, 'utility', 'embedding', 'generation'
+    prompt_tokens         INT NOT NULL DEFAULT 0,
+    completion_tokens     INT NOT NULL DEFAULT 0,
+    cache_creation_tokens INT NOT NULL DEFAULT 0,
+    cache_read_tokens     INT NOT NULL DEFAULT 0,
+    cost_input            NUMERIC(12,6),
+    cost_output           NUMERIC(12,6),
+    created_at            TIMESTAMPTZ NOT NULL DEFAULT NOW()
+);
+
+CREATE INDEX IF NOT EXISTS idx_usage_log_user     ON usage_log(user_id);
+CREATE INDEX IF NOT EXISTS idx_usage_log_created  ON usage_log(created_at);
+CREATE INDEX IF NOT EXISTS idx_usage_log_provider ON usage_log(provider_config_id);
+CREATE INDEX IF NOT EXISTS idx_usage_log_model    ON usage_log(model_id);
+CREATE INDEX IF NOT EXISTS idx_usage_log_scope    ON usage_log(provider_scope);
+
+
+-- =========================================
+-- 21. MODEL PRICING
+-- =========================================
+
+CREATE TABLE IF NOT EXISTS model_pricing (
+    id                  UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    provider_config_id  UUID NOT NULL REFERENCES provider_configs(id) ON DELETE CASCADE,
+    model_id            TEXT NOT NULL,
+    input_per_m         NUMERIC(10,6),
+    output_per_m        NUMERIC(10,6),
+    cache_create_per_m  NUMERIC(10,6),
+    cache_read_per_m    NUMERIC(10,6),
+    currency            TEXT NOT NULL DEFAULT 'USD',
+    source              TEXT NOT NULL DEFAULT 'manual',
+    updated_at          TIMESTAMPTZ DEFAULT NOW(),
+    updated_by          UUID REFERENCES users(id),
+    UNIQUE(provider_config_id, model_id)
+);
+
+
+-- =========================================
+-- 22. EXTENSIONS
+-- =========================================
+
+CREATE TABLE IF NOT EXISTS extensions (
+    id          UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    ext_id      VARCHAR(100) NOT NULL UNIQUE,
+    name        VARCHAR(200) NOT NULL,
+    version     VARCHAR(50)  NOT NULL DEFAULT '0.0.0',
+    tier        VARCHAR(20)  NOT NULL DEFAULT 'browser',
+    description TEXT         NOT NULL DEFAULT '',
+    author      VARCHAR(200) NOT NULL DEFAULT '',
+    manifest    JSONB        NOT NULL DEFAULT '{}',
+    is_system   BOOLEAN      NOT NULL DEFAULT false,
+    is_enabled  BOOLEAN      NOT NULL DEFAULT true,
+    scope       VARCHAR(20)  NOT NULL DEFAULT 'global',
+    team_id     UUID         REFERENCES teams(id) ON DELETE CASCADE,
+    installed_by UUID        REFERENCES users(id) ON DELETE SET NULL,
+    created_at  TIMESTAMPTZ  NOT NULL DEFAULT now(),
+    updated_at  TIMESTAMPTZ  NOT NULL DEFAULT now()
+);
+
+CREATE INDEX IF NOT EXISTS idx_extensions_tier ON extensions(tier);
+CREATE INDEX IF NOT EXISTS idx_extensions_enabled ON extensions(is_enabled) WHERE is_enabled = true;
+
+CREATE TABLE IF NOT EXISTS extension_user_settings (
+    extension_id UUID NOT NULL REFERENCES extensions(id) ON DELETE CASCADE,
+    user_id      UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    settings     JSONB   NOT NULL DEFAULT '{}',
+    is_enabled   BOOLEAN NOT NULL DEFAULT true,
+    PRIMARY KEY (extension_id, user_id)
+);
+
+
+-- =========================================
+-- 23. ATTACHMENTS
+-- =========================================
+
+CREATE TABLE IF NOT EXISTS attachments (
+    id              UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    channel_id      UUID NOT NULL REFERENCES channels(id) ON DELETE CASCADE,
+    user_id         UUID NOT NULL REFERENCES users(id),
+    message_id      UUID REFERENCES messages(id) ON DELETE SET NULL,
+    filename        VARCHAR(255) NOT NULL,
+    content_type    VARCHAR(127) NOT NULL,
+    size_bytes      BIGINT NOT NULL,
+    storage_key     TEXT NOT NULL,
+    extracted_text  TEXT,
+    metadata        JSONB DEFAULT '{}'::jsonb,
+    created_at      TIMESTAMPTZ DEFAULT NOW()
+);
+
+CREATE INDEX IF NOT EXISTS idx_attachments_channel ON attachments(channel_id);
+CREATE INDEX IF NOT EXISTS idx_attachments_user_size ON attachments(user_id);
+CREATE INDEX IF NOT EXISTS idx_attachments_message ON attachments(message_id) WHERE message_id IS NOT NULL;
+CREATE INDEX IF NOT EXISTS idx_attachments_orphan ON attachments(created_at) WHERE message_id IS NULL;
+
+
+-- =========================================
+-- 24. KNOWLEDGE BASES
+-- =========================================
+
+CREATE TABLE IF NOT EXISTS knowledge_bases (
+    id              UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    name            TEXT NOT NULL,
+    description     TEXT NOT NULL DEFAULT '',
+    scope           TEXT NOT NULL DEFAULT 'global',
+    owner_id        UUID REFERENCES users(id) ON DELETE CASCADE,
+    team_id         UUID REFERENCES teams(id) ON DELETE CASCADE,
+    embedding_config JSONB NOT NULL DEFAULT '{}',
+    document_count  INT NOT NULL DEFAULT 0,
+    chunk_count     INT NOT NULL DEFAULT 0,
+    total_bytes     BIGINT NOT NULL DEFAULT 0,
+    status          TEXT NOT NULL DEFAULT 'active',
+    created_at      TIMESTAMPTZ NOT NULL DEFAULT now(),
+    updated_at      TIMESTAMPTZ NOT NULL DEFAULT now(),
+
+    CONSTRAINT kb_scope_check CHECK (
+        (scope = 'global'   AND owner_id IS NULL) OR
+        (scope = 'team'     AND team_id IS NOT NULL) OR
+        (scope = 'personal' AND owner_id IS NOT NULL)
+    )
+);
+
+CREATE INDEX IF NOT EXISTS idx_kb_scope ON knowledge_bases(scope);
+CREATE INDEX IF NOT EXISTS idx_kb_owner ON knowledge_bases(owner_id) WHERE owner_id IS NOT NULL;
+CREATE INDEX IF NOT EXISTS idx_kb_team  ON knowledge_bases(team_id)  WHERE team_id IS NOT NULL;
+
+CREATE TABLE IF NOT EXISTS kb_documents (
+    id              UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    kb_id           UUID NOT NULL REFERENCES knowledge_bases(id) ON DELETE CASCADE,
+    filename        TEXT NOT NULL,
+    content_type    TEXT NOT NULL,
+    size_bytes      BIGINT NOT NULL,
+    storage_key     TEXT NOT NULL,
+    extracted_text  TEXT,
+    chunk_count     INT NOT NULL DEFAULT 0,
+    status          TEXT NOT NULL DEFAULT 'pending',
+    error           TEXT,
+    uploaded_by     UUID NOT NULL REFERENCES users(id),
+    created_at      TIMESTAMPTZ NOT NULL DEFAULT now(),
+    updated_at      TIMESTAMPTZ NOT NULL DEFAULT now()
+);
+
+CREATE INDEX IF NOT EXISTS idx_kbdoc_kb ON kb_documents(kb_id);
+
+CREATE TABLE IF NOT EXISTS kb_chunks (
+    id              UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    kb_id           UUID NOT NULL REFERENCES knowledge_bases(id) ON DELETE CASCADE,
+    document_id     UUID NOT NULL REFERENCES kb_documents(id) ON DELETE CASCADE,
+    chunk_index     INT NOT NULL,
+    content         TEXT NOT NULL,
+    token_count     INT NOT NULL DEFAULT 0,
+    embedding       VECTOR(3072),
+    metadata        JSONB NOT NULL DEFAULT '{}',
+    created_at      TIMESTAMPTZ NOT NULL DEFAULT now()
+);
+
+CREATE INDEX IF NOT EXISTS idx_kbchunk_kb  ON kb_chunks(kb_id);
+CREATE INDEX IF NOT EXISTS idx_kbchunk_doc ON kb_chunks(document_id);
+
+-- NOTE: IVFFlat index for similarity search created after first data load
+-- (needs rows to train). The ingest handler creates it.
+
+CREATE TABLE IF NOT EXISTS channel_knowledge_bases (
+    channel_id      UUID NOT NULL REFERENCES channels(id) ON DELETE CASCADE,
+    kb_id           UUID NOT NULL REFERENCES knowledge_bases(id) ON DELETE CASCADE,
+    enabled         BOOLEAN NOT NULL DEFAULT true,
+    added_at        TIMESTAMPTZ NOT NULL DEFAULT now(),
+    PRIMARY KEY (channel_id, kb_id)
+);
diff --git a/server/database/migrations/002_ci_username.sql b/server/database/migrations/002_ci_username.sql
deleted file mode 100644
index 4f18dc9..0000000
--- a/server/database/migrations/002_ci_username.sql
+++ /dev/null
@@ -1,14 +0,0 @@
--- 002_ci_username.sql
--- Case-insensitive unique indexes for username and email.
--- Replaces the default UNIQUE constraint (which is case-sensitive).
-
--- Normalize existing rows to lowercase first
-UPDATE users SET username = LOWER(username) WHERE username != LOWER(username);
-UPDATE users SET email = LOWER(email) WHERE email != LOWER(email);
-
--- Drop old case-sensitive unique constraints and add case-insensitive indexes
-ALTER TABLE users DROP CONSTRAINT IF EXISTS users_username_key;
-ALTER TABLE users DROP CONSTRAINT IF EXISTS users_email_key;
-
-CREATE UNIQUE INDEX IF NOT EXISTS users_username_ci ON users (LOWER(username));
-CREATE UNIQUE INDEX IF NOT EXISTS users_email_ci ON users (LOWER(email));
diff --git a/server/database/migrations/003_vault.sql b/server/database/migrations/003_vault.sql
deleted file mode 100644
index bba289d..0000000
--- a/server/database/migrations/003_vault.sql
+++ /dev/null
@@ -1,48 +0,0 @@
--- 003_vault.sql — API Key Encryption + User Vault
--- v0.9.4: Two-tier encryption for API keys
---
--- Phase 1 (this migration): Add new columns alongside existing plaintext.
--- Phase 2 (Go startup):     Backfill — encrypt plaintext keys, generate UEKs.
--- Phase 3 (future):         Drop api_key_plain after confirmed stable.
-
--- =========================================
--- 1. USERS — Vault support
--- =========================================
--- Per-user encryption key (UEK) wrapped with password-derived key (Argon2id).
--- UEK protects personal BYOK API keys. Platform admin cannot recover without
--- the user's password.
-
-ALTER TABLE users ADD COLUMN IF NOT EXISTS encrypted_uek BYTEA;
-ALTER TABLE users ADD COLUMN IF NOT EXISTS uek_salt      BYTEA;
-ALTER TABLE users ADD COLUMN IF NOT EXISTS uek_nonce     BYTEA;
-ALTER TABLE users ADD COLUMN IF NOT EXISTS vault_set     BOOLEAN NOT NULL DEFAULT false;
-
-COMMENT ON COLUMN users.encrypted_uek IS 'UEK encrypted with Argon2id(password)-derived key';
-COMMENT ON COLUMN users.uek_salt      IS 'Argon2id salt for UEK derivation';
-COMMENT ON COLUMN users.uek_nonce     IS 'AES-GCM nonce for UEK wrapping';
-COMMENT ON COLUMN users.vault_set     IS 'true once UEK has been generated and wrapped';
-
--- =========================================
--- 2. PROVIDER_CONFIGS — Encrypted key storage
--- =========================================
--- Rename current plaintext column, add encrypted BYTEA columns.
--- Backfill happens in Go (needs ENCRYPTION_KEY env var).
-
--- Keep plaintext temporarily for backfill; Go startup reads it, encrypts,
--- writes to new columns, then NULLs it out.
-ALTER TABLE provider_configs RENAME COLUMN api_key_enc TO api_key_plain;
-ALTER TABLE provider_configs ADD COLUMN IF NOT EXISTS api_key_enc   BYTEA;
-ALTER TABLE provider_configs ADD COLUMN IF NOT EXISTS key_nonce     BYTEA;
-ALTER TABLE provider_configs ADD COLUMN IF NOT EXISTS key_scope     TEXT;
-
--- Backfill key_scope from existing scope column (safe default)
-UPDATE provider_configs SET key_scope = scope WHERE key_scope IS NULL;
-
--- Now make it NOT NULL with default
-ALTER TABLE provider_configs ALTER COLUMN key_scope SET NOT NULL;
-ALTER TABLE provider_configs ALTER COLUMN key_scope SET DEFAULT 'global';
-
-COMMENT ON COLUMN provider_configs.api_key_plain IS 'DEPRECATED: plaintext key, cleared after vault backfill';
-COMMENT ON COLUMN provider_configs.api_key_enc   IS 'AES-256-GCM encrypted API key (BYTEA)';
-COMMENT ON COLUMN provider_configs.key_nonce     IS 'AES-GCM nonce for api_key_enc';
-COMMENT ON COLUMN provider_configs.key_scope     IS 'Encryption tier: global/team use env key, personal uses UEK';
diff --git a/server/database/migrations/004_roles_usage.sql b/server/database/migrations/004_roles_usage.sql
deleted file mode 100644
index a77fec7..0000000
--- a/server/database/migrations/004_roles_usage.sql
+++ /dev/null
@@ -1,64 +0,0 @@
--- 004_roles_usage.sql
--- v0.10.0: Model Roles + Usage Tracking
---
--- New tables: usage_log, model_pricing
--- Seed: model_roles in global_settings
-
--- ── Model roles seed ──────────────────────────
--- Uses existing global_settings table. No new tables for roles.
--- Team overrides go in teams.settings JSONB (existing column).
-
-INSERT INTO global_settings (key, value) VALUES
-    ('model_roles', '{
-        "utility":    { "primary": null, "fallback": null },
-        "embedding":  { "primary": null, "fallback": null },
-        "generation": { "primary": null, "fallback": null }
-    }'::jsonb)
-ON CONFLICT (key) DO NOTHING;
-
--- ── Usage tracking ────────────────────────────
--- Every completion (streaming and non-streaming) logs token counts and cost.
--- Cost is calculated at insert time from model_pricing.
--- provider_scope is denormalized for efficient admin filtering (excludes BYOK).
-
-CREATE TABLE IF NOT EXISTS usage_log (
-    id                    UUID PRIMARY KEY DEFAULT gen_random_uuid(),
-    channel_id            UUID REFERENCES channels(id) ON DELETE SET NULL,
-    user_id               UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
-    provider_config_id    UUID REFERENCES provider_configs(id) ON DELETE SET NULL,
-    provider_scope        TEXT NOT NULL DEFAULT 'global',
-    model_id              TEXT NOT NULL,
-    role                  TEXT,  -- NULL = user chat, 'utility', 'embedding', 'generation'
-    prompt_tokens         INT NOT NULL DEFAULT 0,
-    completion_tokens     INT NOT NULL DEFAULT 0,
-    cache_creation_tokens INT NOT NULL DEFAULT 0,
-    cache_read_tokens     INT NOT NULL DEFAULT 0,
-    cost_input            NUMERIC(12,6),
-    cost_output           NUMERIC(12,6),
-    created_at            TIMESTAMPTZ NOT NULL DEFAULT NOW()
-);
-
-CREATE INDEX IF NOT EXISTS idx_usage_log_user     ON usage_log(user_id);
-CREATE INDEX IF NOT EXISTS idx_usage_log_created  ON usage_log(created_at);
-CREATE INDEX IF NOT EXISTS idx_usage_log_provider ON usage_log(provider_config_id);
-CREATE INDEX IF NOT EXISTS idx_usage_log_model    ON usage_log(model_id);
-CREATE INDEX IF NOT EXISTS idx_usage_log_scope    ON usage_log(provider_scope);
-
--- ── Model pricing ─────────────────────────────
--- Two sources: 'catalog' (auto-populated from provider API sync) and
--- 'manual' (admin override). Manual entries are never overwritten by sync.
-
-CREATE TABLE IF NOT EXISTS model_pricing (
-    id                  UUID PRIMARY KEY DEFAULT gen_random_uuid(),
-    provider_config_id  UUID NOT NULL REFERENCES provider_configs(id) ON DELETE CASCADE,
-    model_id            TEXT NOT NULL,
-    input_per_m         NUMERIC(10,6),
-    output_per_m        NUMERIC(10,6),
-    cache_create_per_m  NUMERIC(10,6),
-    cache_read_per_m    NUMERIC(10,6),
-    currency            TEXT NOT NULL DEFAULT 'USD',
-    source              TEXT NOT NULL DEFAULT 'manual',
-    updated_at          TIMESTAMPTZ DEFAULT NOW(),
-    updated_by          UUID REFERENCES users(id),
-    UNIQUE(provider_config_id, model_id)
-);
diff --git a/server/database/migrations/005_model_type.sql b/server/database/migrations/005_model_type.sql
deleted file mode 100644
index 9945e3f..0000000
--- a/server/database/migrations/005_model_type.sql
+++ /dev/null
@@ -1,14 +0,0 @@
--- Migration 005: Add model_type to model_catalog
---
--- Providers like Venice return a "type" field per model (e.g. "text", "embedding", "image").
--- This column captures that classification so role dropdowns can filter appropriately:
---   - "embedding" role → only embedding models
---   - "utility" role → only chat/text models
---
--- Default is "chat" (the overwhelming majority of models). Provider sync will
--- populate from the wire response when available — NO hardcoding of model types.
-
-ALTER TABLE model_catalog ADD COLUMN IF NOT EXISTS model_type VARCHAR(20) DEFAULT 'chat';
-
--- Index for role UI filtering (e.g. "show me all embedding models for this provider")
-CREATE INDEX IF NOT EXISTS idx_model_catalog_type ON model_catalog(model_type);
diff --git a/server/database/migrations/006_extensions.sql b/server/database/migrations/006_extensions.sql
deleted file mode 100644
index 918e5e7..0000000
--- a/server/database/migrations/006_extensions.sql
+++ /dev/null
@@ -1,41 +0,0 @@
--- Migration 006: Extension system tables
---
--- Extensions are installable plugins that add renderers, tools, surfaces,
--- and event handlers. Three tiers: browser (JS), starlark (sandbox),
--- sidecar (container). Browser tier ships first (v0.11.0).
---
--- See EXTENSIONS.md for full spec.
-
--- ── Extension registry ──────────────────────────
-
-CREATE TABLE IF NOT EXISTS extensions (
-    id          UUID PRIMARY KEY DEFAULT gen_random_uuid(),
-    ext_id      VARCHAR(100) NOT NULL UNIQUE,       -- manifest id (e.g. "collapsible-code")
-    name        VARCHAR(200) NOT NULL,               -- human label
-    version     VARCHAR(50)  NOT NULL DEFAULT '0.0.0',
-    tier        VARCHAR(20)  NOT NULL DEFAULT 'browser',  -- browser | starlark | sidecar
-    description TEXT         NOT NULL DEFAULT '',
-    author      VARCHAR(200) NOT NULL DEFAULT '',
-    manifest    JSONB        NOT NULL DEFAULT '{}',  -- full manifest JSON
-    is_system   BOOLEAN      NOT NULL DEFAULT false, -- admin-pushed, users can't disable
-    is_enabled  BOOLEAN      NOT NULL DEFAULT true,  -- global enable/disable
-    scope       VARCHAR(20)  NOT NULL DEFAULT 'global', -- global | team | personal
-    team_id     UUID         REFERENCES teams(id) ON DELETE CASCADE,
-    installed_by UUID        REFERENCES users(id) ON DELETE SET NULL,
-    created_at  TIMESTAMPTZ  NOT NULL DEFAULT now(),
-    updated_at  TIMESTAMPTZ  NOT NULL DEFAULT now()
-);
-
--- For bundled extensions that ship with core
-CREATE INDEX IF NOT EXISTS idx_extensions_tier ON extensions(tier);
-CREATE INDEX IF NOT EXISTS idx_extensions_enabled ON extensions(is_enabled) WHERE is_enabled = true;
-
--- ── Per-user extension settings ─────────────────
-
-CREATE TABLE IF NOT EXISTS extension_user_settings (
-    extension_id UUID NOT NULL REFERENCES extensions(id) ON DELETE CASCADE,
-    user_id      UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
-    settings     JSONB   NOT NULL DEFAULT '{}',  -- user's config values
-    is_enabled   BOOLEAN NOT NULL DEFAULT true,   -- per-user toggle
-    PRIMARY KEY (extension_id, user_id)
-);
diff --git a/server/database/migrations/007_attachments.sql b/server/database/migrations/007_attachments.sql
deleted file mode 100644
index b13227a..0000000
--- a/server/database/migrations/007_attachments.sql
+++ /dev/null
@@ -1,32 +0,0 @@
--- 007_attachments.sql
--- File attachments for chat messages (v0.12.0)
---
--- Blobs live in object storage (PVC / S3). This table holds metadata.
--- Access control: always join through channels — attachments inherit
--- channel membership as their access boundary.
-
-CREATE TABLE IF NOT EXISTS attachments (
-    id              UUID PRIMARY KEY DEFAULT gen_random_uuid(),
-    channel_id      UUID NOT NULL REFERENCES channels(id) ON DELETE CASCADE,
-    user_id         UUID NOT NULL REFERENCES users(id),
-    message_id      UUID REFERENCES messages(id) ON DELETE SET NULL,
-    filename        VARCHAR(255) NOT NULL,
-    content_type    VARCHAR(127) NOT NULL,
-    size_bytes      BIGINT NOT NULL,
-    storage_key     TEXT NOT NULL,
-    extracted_text  TEXT,
-    metadata        JSONB DEFAULT '{}'::jsonb,
-    created_at      TIMESTAMPTZ DEFAULT NOW()
-);
-
--- Primary access pattern: find attachments for a channel (auth check joins here)
-CREATE INDEX IF NOT EXISTS idx_attachments_channel ON attachments(channel_id);
-
--- Quota calculation: SUM(size_bytes) WHERE user_id = $1
-CREATE INDEX IF NOT EXISTS idx_attachments_user_size ON attachments(user_id);
-
--- Find attachments for a specific message
-CREATE INDEX IF NOT EXISTS idx_attachments_message ON attachments(message_id) WHERE message_id IS NOT NULL;
-
--- Orphan cleanup: find unlinked attachments older than threshold
-CREATE INDEX IF NOT EXISTS idx_attachments_orphan ON attachments(created_at) WHERE message_id IS NULL;
diff --git a/server/database/migrations/008_knowledge_bases.sql b/server/database/migrations/008_knowledge_bases.sql
deleted file mode 100644
index 6981438..0000000
--- a/server/database/migrations/008_knowledge_bases.sql
+++ /dev/null
@@ -1,99 +0,0 @@
--- 008_knowledge_bases.sql
--- Knowledge Bases: KB metadata, documents, chunks, channel links.
--- Requires: pgvector extension already installed (via db-bootstrap.sh).
-
--- ── Knowledge Bases ──────────────────────────
-
-CREATE TABLE IF NOT EXISTS knowledge_bases (
-    id              UUID PRIMARY KEY DEFAULT gen_random_uuid(),
-    name            TEXT NOT NULL,
-    description     TEXT NOT NULL DEFAULT '',
-    scope           TEXT NOT NULL DEFAULT 'global',  -- global, team, personal
-    owner_id        UUID REFERENCES users(id) ON DELETE CASCADE,
-    team_id         UUID REFERENCES teams(id) ON DELETE CASCADE,
-
-    -- Snapshot of embedding config at creation time.
-    -- Changing the model requires a full re-embed (rebuild endpoint).
-    -- { "provider_config_id": "...", "model_id": "...", "dimensions": 1536 }
-    embedding_config JSONB NOT NULL DEFAULT '{}',
-
-    -- Denormalized stats, updated by ingest pipeline.
-    document_count  INT NOT NULL DEFAULT 0,
-    chunk_count     INT NOT NULL DEFAULT 0,
-    total_bytes     BIGINT NOT NULL DEFAULT 0,
-
-    status          TEXT NOT NULL DEFAULT 'active',  -- active, processing, error
-    created_at      TIMESTAMPTZ NOT NULL DEFAULT now(),
-    updated_at      TIMESTAMPTZ NOT NULL DEFAULT now(),
-
-    CONSTRAINT kb_scope_check CHECK (
-        (scope = 'global'   AND owner_id IS NULL) OR
-        (scope = 'team'     AND team_id IS NOT NULL) OR
-        (scope = 'personal' AND owner_id IS NOT NULL)
-    )
-);
-
-CREATE INDEX IF NOT EXISTS idx_kb_scope ON knowledge_bases(scope);
-CREATE INDEX IF NOT EXISTS idx_kb_owner ON knowledge_bases(owner_id) WHERE owner_id IS NOT NULL;
-CREATE INDEX IF NOT EXISTS idx_kb_team  ON knowledge_bases(team_id)  WHERE team_id IS NOT NULL;
-
--- ── KB Documents ─────────────────────────────
--- One row per uploaded file. Blobs live in ObjectStore under:
---   kb/{kb_id}/{doc_id}_{filename}
-
-CREATE TABLE IF NOT EXISTS kb_documents (
-    id              UUID PRIMARY KEY DEFAULT gen_random_uuid(),
-    kb_id           UUID NOT NULL REFERENCES knowledge_bases(id) ON DELETE CASCADE,
-    filename        TEXT NOT NULL,
-    content_type    TEXT NOT NULL,
-    size_bytes      BIGINT NOT NULL,
-    storage_key     TEXT NOT NULL,
-    extracted_text  TEXT,                     -- full text for re-chunking
-    chunk_count     INT NOT NULL DEFAULT 0,
-    status          TEXT NOT NULL DEFAULT 'pending',  -- pending, chunking, embedding, ready, error
-    error           TEXT,
-    uploaded_by     UUID NOT NULL REFERENCES users(id),
-    created_at      TIMESTAMPTZ NOT NULL DEFAULT now(),
-    updated_at      TIMESTAMPTZ NOT NULL DEFAULT now()
-);
-
-CREATE INDEX IF NOT EXISTS idx_kbdoc_kb ON kb_documents(kb_id);
-
--- ── KB Chunks ────────────────────────────────
--- Chunked text + embedding vector for similarity search.
--- vector(3072) accommodates all current embedding models:
---   OpenAI ada-002 / text-embedding-3-small = 1536
---   OpenAI text-embedding-3-large = 3072
---   Open-source models = typically 768-1024
--- Smaller vectors are zero-padded at insert time.
-
-CREATE TABLE IF NOT EXISTS kb_chunks (
-    id              UUID PRIMARY KEY DEFAULT gen_random_uuid(),
-    kb_id           UUID NOT NULL REFERENCES knowledge_bases(id) ON DELETE CASCADE,
-    document_id     UUID NOT NULL REFERENCES kb_documents(id) ON DELETE CASCADE,
-    chunk_index     INT NOT NULL,
-    content         TEXT NOT NULL,
-    token_count     INT NOT NULL DEFAULT 0,
-    embedding       VECTOR(3072),
-    metadata        JSONB NOT NULL DEFAULT '{}',
-    created_at      TIMESTAMPTZ NOT NULL DEFAULT now()
-);
-
-CREATE INDEX IF NOT EXISTS idx_kbchunk_kb  ON kb_chunks(kb_id);
-CREATE INDEX IF NOT EXISTS idx_kbchunk_doc ON kb_chunks(document_id);
-
--- NOTE: IVFFlat index for similarity search is created after first data
--- load (needs rows to train). The ingest handler creates it:
---   CREATE INDEX idx_kbchunk_embedding ON kb_chunks
---       USING ivfflat (embedding vector_cosine_ops) WITH (lists = 100);
-
--- ── Channel-KB Links ─────────────────────────
--- Which KBs are active for a given channel.
-
-CREATE TABLE IF NOT EXISTS channel_knowledge_bases (
-    channel_id      UUID NOT NULL REFERENCES channels(id) ON DELETE CASCADE,
-    kb_id           UUID NOT NULL REFERENCES knowledge_bases(id) ON DELETE CASCADE,
-    enabled         BOOLEAN NOT NULL DEFAULT true,
-    added_at        TIMESTAMPTZ NOT NULL DEFAULT now(),
-    PRIMARY KEY (channel_id, kb_id)
-);
\ No newline at end of file
diff --git a/server/database/migrations/009_notes_embedding.sql b/server/database/migrations/009_notes_embedding.sql
deleted file mode 100644
index 633b6de..0000000
--- a/server/database/migrations/009_notes_embedding.sql
+++ /dev/null
@@ -1,12 +0,0 @@
--- 009_notes_embedding.sql
--- Adds vector embedding column to notes for semantic search.
--- Uses the same vector(3072) dimension as kb_chunks for uniformity.
-
-ALTER TABLE notes ADD COLUMN IF NOT EXISTS embedding vector(3072);
-
--- NOTE: pgvector HNSW indexes are limited to 2000 dimensions.
--- For 3072-dim vectors, IVFFlat is the option but requires training
--- data (rows). The notes table is typically small enough that a
--- sequential scan is fast. If needed, create after data exists:
---   CREATE INDEX idx_notes_embedding ON notes
---       USING ivfflat (embedding vector_cosine_ops) WITH (lists = 100);
diff --git a/server/database/testhelper.go b/server/database/testhelper.go
index 01410fd..fa30f3c 100644
--- a/server/database/testhelper.go
+++ b/server/database/testhelper.go
@@ -165,6 +165,9 @@ func TruncateAll(t *testing.T) {
 	}
 	// Order matters due to foreign keys — truncate with CASCADE
 	tables := []string{
+		"resource_grants",
+		"group_members",
+		"groups",
 		"usage_log",
 		"model_pricing",
 		"notes",
@@ -256,6 +259,64 @@ func SeedTestChannel(t *testing.T, userID, title string) string {
 
 // ── Helpers ─────────────────────────────────
 
+// SeedTestTeam creates a test team and returns the team ID.
+func SeedTestTeam(t *testing.T, name, createdBy string) string {
+	t.Helper()
+	var id string
+	err := DB.QueryRow(`
+		INSERT INTO teams (name, created_by)
+		VALUES ($1, $2)
+		RETURNING id
+	`, name, createdBy).Scan(&id)
+	if err != nil {
+		t.Fatalf("SeedTestTeam: %v", err)
+	}
+	return id
+}
+
+// SeedTestTeamMember adds a user to a team.
+func SeedTestTeamMember(t *testing.T, teamID, userID, role string) {
+	t.Helper()
+	_, err := DB.Exec(`
+		INSERT INTO team_members (team_id, user_id, role)
+		VALUES ($1, $2, $3)
+	`, teamID, userID, role)
+	if err != nil {
+		t.Fatalf("SeedTestTeamMember: %v", err)
+	}
+}
+
+// SeedTestGroup creates a test group and returns the group ID.
+func SeedTestGroup(t *testing.T, name, scope string, teamID *string, createdBy string) string {
+	t.Helper()
+	var id string
+	var teamArg interface{}
+	if teamID != nil {
+		teamArg = *teamID
+	}
+	err := DB.QueryRow(`
+		INSERT INTO groups (name, scope, team_id, created_by)
+		VALUES ($1, $2, $3, $4)
+		RETURNING id
+	`, name, scope, teamArg, createdBy).Scan(&id)
+	if err != nil {
+		t.Fatalf("SeedTestGroup: %v", err)
+	}
+	return id
+}
+
+// SeedGroupMember adds a user to a group.
+func SeedGroupMember(t *testing.T, groupID, userID, addedBy string) {
+	t.Helper()
+	_, err := DB.Exec(`
+		INSERT INTO group_members (group_id, user_id, added_by)
+		VALUES ($1, $2, $3)
+	`, groupID, userID, addedBy)
+	if err != nil {
+		t.Fatalf("SeedGroupMember: %v", err)
+	}
+}
+
 func envOr(key, fallback string) string {
 	if v := os.Getenv(key); v != "" {
 		return v
diff --git a/server/handlers/groups.go b/server/handlers/groups.go
new file mode 100644
index 0000000..7ecd36f
--- /dev/null
+++ b/server/handlers/groups.go
@@ -0,0 +1,365 @@
+package handlers
+
+import (
+	"database/sql"
+	"net/http"
+	"strings"
+
+	"github.com/gin-gonic/gin"
+
+	"git.gobha.me/xcaliber/chat-switchboard/models"
+	"git.gobha.me/xcaliber/chat-switchboard/store"
+)
+
+// ── Request types ───────────────────────────
+
+type createGroupRequest struct {
+	Name        string  `json:"name" binding:"required,min=1,max=200"`
+	Description string  `json:"description,omitempty"`
+	Scope       string  `json:"scope" binding:"required,oneof=global team"`
+	TeamID      *string `json:"team_id,omitempty"`
+}
+
+type updateGroupRequest struct {
+	Name        *string `json:"name,omitempty"`
+	Description *string `json:"description,omitempty"`
+}
+
+type addGroupMemberRequest struct {
+	UserID string `json:"user_id" binding:"required"`
+}
+
+type setResourceGrantRequest struct {
+	GrantScope    string   `json:"grant_scope" binding:"required,oneof=team_only global groups"`
+	GrantedGroups []string `json:"granted_groups,omitempty"` // required when grant_scope=groups
+}
+
+// ── Handler ─────────────────────────────────
+
+type GroupHandler struct {
+	stores store.Stores
+}
+
+func NewGroupHandler(s store.Stores) *GroupHandler {
+	return &GroupHandler{stores: s}
+}
+
+// ── Admin: List All Groups ──────────────────
+
+func (h *GroupHandler) ListGroups(c *gin.Context) {
+	groups, err := h.stores.Groups.ListAll(c.Request.Context())
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "query failed"})
+		return
+	}
+	if groups == nil {
+		groups = []models.Group{}
+	}
+	c.JSON(http.StatusOK, gin.H{"data": groups})
+}
+
+// ── Admin: Create Group ─────────────────────
+
+func (h *GroupHandler) CreateGroup(c *gin.Context) {
+	actorID := getUserID(c)
+
+	var req createGroupRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+
+	// Validate scope constraints
+	if req.Scope == models.ScopeTeam && (req.TeamID == nil || *req.TeamID == "") {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "team_id required for team-scoped groups"})
+		return
+	}
+	if req.Scope == models.ScopeGlobal && req.TeamID != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "team_id must be null for global groups"})
+		return
+	}
+
+	g := &models.Group{
+		Name:        req.Name,
+		Description: req.Description,
+		Scope:       req.Scope,
+		TeamID:      req.TeamID,
+		CreatedBy:   actorID,
+	}
+
+	if err := h.stores.Groups.Create(c.Request.Context(), g); err != nil {
+		if strings.Contains(err.Error(), "duplicate key") {
+			c.JSON(http.StatusConflict, gin.H{"error": "group name already exists in this scope"})
+			return
+		}
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "failed to create group"})
+		return
+	}
+
+	c.JSON(http.StatusCreated, g)
+	AuditLog(c, "group.create", "group", g.ID, map[string]interface{}{
+		"name": g.Name, "scope": g.Scope,
+	})
+}
+
+// ── Admin: Get Group ────────────────────────
+
+func (h *GroupHandler) GetGroup(c *gin.Context) {
+	id := c.Param("id")
+
+	g, err := h.stores.Groups.GetByID(c.Request.Context(), id)
+	if err == sql.ErrNoRows {
+		c.JSON(http.StatusNotFound, gin.H{"error": "group not found"})
+		return
+	}
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "query failed"})
+		return
+	}
+
+	c.JSON(http.StatusOK, g)
+}
+
+// ── Admin: Update Group ─────────────────────
+
+func (h *GroupHandler) UpdateGroup(c *gin.Context) {
+	id := c.Param("id")
+
+	var req updateGroupRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+
+	if req.Name == nil && req.Description == nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "no fields to update"})
+		return
+	}
+
+	err := h.stores.Groups.Update(c.Request.Context(), id, req.Name, req.Description)
+	if err == sql.ErrNoRows {
+		c.JSON(http.StatusNotFound, gin.H{"error": "group not found"})
+		return
+	}
+	if err != nil {
+		if strings.Contains(err.Error(), "duplicate key") {
+			c.JSON(http.StatusConflict, gin.H{"error": "group name already exists in this scope"})
+			return
+		}
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "update failed"})
+		return
+	}
+
+	c.JSON(http.StatusOK, gin.H{"ok": true})
+	AuditLog(c, "group.update", "group", id, nil)
+}
+
+// ── Admin: Delete Group ─────────────────────
+
+func (h *GroupHandler) DeleteGroup(c *gin.Context) {
+	id := c.Param("id")
+
+	err := h.stores.Groups.Delete(c.Request.Context(), id)
+	if err == sql.ErrNoRows {
+		c.JSON(http.StatusNotFound, gin.H{"error": "group not found"})
+		return
+	}
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "delete failed"})
+		return
+	}
+
+	c.JSON(http.StatusOK, gin.H{"ok": true})
+	AuditLog(c, "group.delete", "group", id, nil)
+}
+
+// ── Members: List ───────────────────────────
+
+func (h *GroupHandler) ListMembers(c *gin.Context) {
+	groupID := c.Param("id")
+
+	members, err := h.stores.Groups.ListMembers(c.Request.Context(), groupID)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "query failed"})
+		return
+	}
+	if members == nil {
+		members = []models.GroupMember{}
+	}
+	c.JSON(http.StatusOK, gin.H{"data": members})
+}
+
+// ── Members: Add ────────────────────────────
+
+func (h *GroupHandler) AddMember(c *gin.Context) {
+	groupID := c.Param("id")
+	actorID := getUserID(c)
+
+	var req addGroupMemberRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+
+	// Verify group exists
+	if _, err := h.stores.Groups.GetByID(c.Request.Context(), groupID); err == sql.ErrNoRows {
+		c.JSON(http.StatusNotFound, gin.H{"error": "group not found"})
+		return
+	}
+
+	if err := h.stores.Groups.AddMember(c.Request.Context(), groupID, req.UserID, actorID); err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "failed to add member"})
+		return
+	}
+
+	c.JSON(http.StatusOK, gin.H{"ok": true})
+	AuditLog(c, "group.member.add", "group", groupID, map[string]interface{}{
+		"user_id": req.UserID,
+	})
+}
+
+// ── Members: Remove ─────────────────────────
+
+func (h *GroupHandler) RemoveMember(c *gin.Context) {
+	groupID := c.Param("id")
+	userID := c.Param("userId")
+
+	err := h.stores.Groups.RemoveMember(c.Request.Context(), groupID, userID)
+	if err == sql.ErrNoRows {
+		c.JSON(http.StatusNotFound, gin.H{"error": "member not found"})
+		return
+	}
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "failed to remove member"})
+		return
+	}
+
+	c.JSON(http.StatusOK, gin.H{"ok": true})
+	AuditLog(c, "group.member.remove", "group", groupID, map[string]interface{}{
+		"user_id": userID,
+	})
+}
+
+// ── User: My Groups ─────────────────────────
+
+func (h *GroupHandler) MyGroups(c *gin.Context) {
+	userID := getUserID(c)
+
+	groups, err := h.stores.Groups.ListForUser(c.Request.Context(), userID)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "query failed"})
+		return
+	}
+	if groups == nil {
+		groups = []models.Group{}
+	}
+	c.JSON(http.StatusOK, gin.H{"data": groups})
+}
+
+// ── Team Admin: List Team Groups ────────────
+
+func (h *GroupHandler) ListTeamGroups(c *gin.Context) {
+	teamID := getTeamID(c)
+
+	groups, err := h.stores.Groups.ListForTeam(c.Request.Context(), teamID)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "query failed"})
+		return
+	}
+	if groups == nil {
+		groups = []models.Group{}
+	}
+	c.JSON(http.StatusOK, gin.H{"data": groups})
+}
+
+// ── Resource Grants ─────────────────────────
+
+// GetResourceGrant returns the grant for a resource.
+// GET /api/v1/admin/grants/:type/:id
+func (h *GroupHandler) GetResourceGrant(c *gin.Context) {
+	resourceType := c.Param("type")
+	resourceID := c.Param("id")
+
+	grant, err := h.stores.ResourceGrants.Get(c.Request.Context(), resourceType, resourceID)
+	if err == sql.ErrNoRows {
+		// No grant = default team_only behavior
+		c.JSON(http.StatusOK, gin.H{
+			"resource_type":  resourceType,
+			"resource_id":    resourceID,
+			"grant_scope":    models.GrantScopeTeamOnly,
+			"granted_groups": []string{},
+		})
+		return
+	}
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "query failed"})
+		return
+	}
+	c.JSON(http.StatusOK, grant)
+}
+
+// SetResourceGrant creates or updates a grant for a resource.
+// PUT /api/v1/admin/grants/:type/:id
+func (h *GroupHandler) SetResourceGrant(c *gin.Context) {
+	resourceType := c.Param("type")
+	resourceID := c.Param("id")
+	actorID := getUserID(c)
+
+	var req setResourceGrantRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+
+	// Validate: groups scope requires at least one group
+	if req.GrantScope == models.GrantScopeGroups && len(req.GrantedGroups) == 0 {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "granted_groups required when grant_scope is 'groups'"})
+		return
+	}
+
+	// team_only = delete any existing grant (reverts to default scope behavior)
+	if req.GrantScope == models.GrantScopeTeamOnly {
+		_ = h.stores.ResourceGrants.Delete(c.Request.Context(), resourceType, resourceID)
+		c.JSON(http.StatusOK, gin.H{"ok": true})
+		AuditLog(c, "grant.revoke", resourceType, resourceID, nil)
+		return
+	}
+
+	grant := &models.ResourceGrant{
+		ResourceType:  resourceType,
+		ResourceID:    resourceID,
+		GrantScope:    req.GrantScope,
+		GrantedGroups: req.GrantedGroups,
+		CreatedBy:     actorID,
+	}
+
+	if err := h.stores.ResourceGrants.Set(c.Request.Context(), grant); err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "failed to set grant"})
+		return
+	}
+
+	c.JSON(http.StatusOK, grant)
+	AuditLog(c, "grant.set", resourceType, resourceID, map[string]interface{}{
+		"grant_scope": req.GrantScope,
+	})
+}
+
+// DeleteResourceGrant removes a grant for a resource.
+// DELETE /api/v1/admin/grants/:type/:id
+func (h *GroupHandler) DeleteResourceGrant(c *gin.Context) {
+	resourceType := c.Param("type")
+	resourceID := c.Param("id")
+
+	err := h.stores.ResourceGrants.Delete(c.Request.Context(), resourceType, resourceID)
+	if err == sql.ErrNoRows {
+		c.JSON(http.StatusNotFound, gin.H{"error": "grant not found"})
+		return
+	}
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "delete failed"})
+		return
+	}
+
+	c.JSON(http.StatusOK, gin.H{"ok": true})
+	AuditLog(c, "grant.delete", resourceType, resourceID, nil)
+}
diff --git a/server/handlers/integration_test.go b/server/handlers/integration_test.go
index c05f0f6..1a19ba4 100644
--- a/server/handlers/integration_test.go
+++ b/server/handlers/integration_test.go
@@ -16,6 +16,7 @@ import (
 	"git.gobha.me/xcaliber/chat-switchboard/config"
 	"git.gobha.me/xcaliber/chat-switchboard/database"
 	"git.gobha.me/xcaliber/chat-switchboard/middleware"
+	"git.gobha.me/xcaliber/chat-switchboard/models"
 	"git.gobha.me/xcaliber/chat-switchboard/roles"
 	postgres "git.gobha.me/xcaliber/chat-switchboard/store/postgres"
 )
@@ -185,6 +186,25 @@ func setupHarness(t *testing.T) *testHarness {
 	admin.GET("/presets", presets.ListAdminPersonas)
 	admin.POST("/presets", presets.CreateAdminPersona)
 
+	// Admin groups (v0.16.0)
+	groupAdm := NewGroupHandler(stores)
+	admin.GET("/groups", groupAdm.ListGroups)
+	admin.POST("/groups", groupAdm.CreateGroup)
+	admin.GET("/groups/:id", groupAdm.GetGroup)
+	admin.PUT("/groups/:id", groupAdm.UpdateGroup)
+	admin.DELETE("/groups/:id", groupAdm.DeleteGroup)
+	admin.GET("/groups/:id/members", groupAdm.ListMembers)
+	admin.POST("/groups/:id/members", groupAdm.AddMember)
+	admin.DELETE("/groups/:id/members/:userId", groupAdm.RemoveMember)
+
+	// Admin resource grants (v0.16.0)
+	admin.GET("/grants/:type/:id", groupAdm.GetResourceGrant)
+	admin.PUT("/grants/:type/:id", groupAdm.SetResourceGrant)
+	admin.DELETE("/grants/:type/:id", groupAdm.DeleteResourceGrant)
+
+	// User groups (v0.16.0)
+	protected.GET("/groups/mine", groupAdm.MyGroups)
+
 	// Admin roles
 	rolesH := NewRolesHandler(stores, roleResolver)
 	admin.GET("/roles", rolesH.ListRoles)
@@ -2443,3 +2463,397 @@ func TestIntegration_ChannelKBLinking(t *testing.T) {
 		t.Fatalf("channel should have 0 linked KBs after unlink, got %d", len(emptyData))
 	}
 }
+
+// ══════════════════════════════════════════════
+// GROUPS + RESOURCE GRANTS (v0.16.0)
+// ══════════════════════════════════════════════
+
+func TestGroupCRUD(t *testing.T) {
+	h := setupHarness(t)
+
+	_, adminToken := h.createAdminUser("gadmin", "gadmin@test.com")
+
+	// ── Create global group ──
+	w := h.request("POST", "/api/v1/admin/groups", adminToken, map[string]interface{}{
+		"name":        "Engineering",
+		"description": "All engineers",
+		"scope":       "global",
+	})
+	if w.Code != http.StatusCreated {
+		t.Fatalf("create group: want 201, got %d: %s", w.Code, w.Body.String())
+	}
+	var created models.Group
+	decode(w, &created)
+	if created.ID == "" || created.Name != "Engineering" || created.Scope != "global" {
+		t.Fatalf("unexpected group: %+v", created)
+	}
+
+	// ── List groups ──
+	w = h.request("GET", "/api/v1/admin/groups", adminToken, nil)
+	if w.Code != http.StatusOK {
+		t.Fatalf("list groups: want 200, got %d", w.Code)
+	}
+	var listResp map[string]interface{}
+	decode(w, &listResp)
+	data := listResp["data"].([]interface{})
+	if len(data) != 1 {
+		t.Fatalf("expected 1 group, got %d", len(data))
+	}
+
+	// ── Get group ──
+	w = h.request("GET", "/api/v1/admin/groups/"+created.ID, adminToken, nil)
+	if w.Code != http.StatusOK {
+		t.Fatalf("get group: want 200, got %d", w.Code)
+	}
+
+	// ── Update group ──
+	w = h.request("PUT", "/api/v1/admin/groups/"+created.ID, adminToken, map[string]interface{}{
+		"name": "Platform Engineering",
+	})
+	if w.Code != http.StatusOK {
+		t.Fatalf("update group: want 200, got %d: %s", w.Code, w.Body.String())
+	}
+
+	// Verify update
+	w = h.request("GET", "/api/v1/admin/groups/"+created.ID, adminToken, nil)
+	var updated models.Group
+	decode(w, &updated)
+	if updated.Name != "Platform Engineering" {
+		t.Fatalf("name should be updated, got %q", updated.Name)
+	}
+
+	// ── Duplicate name conflict ──
+	w = h.request("POST", "/api/v1/admin/groups", adminToken, map[string]interface{}{
+		"name":  "Platform Engineering",
+		"scope": "global",
+	})
+	if w.Code != http.StatusConflict {
+		t.Fatalf("duplicate name: want 409, got %d", w.Code)
+	}
+
+	// ── Delete group ──
+	w = h.request("DELETE", "/api/v1/admin/groups/"+created.ID, adminToken, nil)
+	if w.Code != http.StatusOK {
+		t.Fatalf("delete group: want 200, got %d", w.Code)
+	}
+
+	// Verify deleted
+	w = h.request("GET", "/api/v1/admin/groups/"+created.ID, adminToken, nil)
+	if w.Code != http.StatusNotFound {
+		t.Fatalf("deleted group: want 404, got %d", w.Code)
+	}
+}
+
+func TestGroupMembers(t *testing.T) {
+	h := setupHarness(t)
+
+	_, adminToken := h.createAdminUser("gmadmin", "gmadmin@test.com")
+	userID := database.SeedTestUser(h.t, "gmuser", "gmuser@test.com")
+	database.TestDB.Exec("UPDATE users SET is_active = true WHERE id = $1", userID)
+	userToken := makeToken(userID, "gmuser@test.com", "user")
+
+	// Create group
+	w := h.request("POST", "/api/v1/admin/groups", adminToken, map[string]interface{}{
+		"name":  "Testers",
+		"scope": "global",
+	})
+	var group models.Group
+	decode(w, &group)
+
+	// ── Add member ──
+	w = h.request("POST", "/api/v1/admin/groups/"+group.ID+"/members", adminToken, map[string]interface{}{
+		"user_id": userID,
+	})
+	if w.Code != http.StatusOK {
+		t.Fatalf("add member: want 200, got %d: %s", w.Code, w.Body.String())
+	}
+
+	// ── List members ──
+	w = h.request("GET", "/api/v1/admin/groups/"+group.ID+"/members", adminToken, nil)
+	if w.Code != http.StatusOK {
+		t.Fatalf("list members: want 200, got %d", w.Code)
+	}
+	var memberResp map[string]interface{}
+	decode(w, &memberResp)
+	members := memberResp["data"].([]interface{})
+	if len(members) != 1 {
+		t.Fatalf("expected 1 member, got %d", len(members))
+	}
+	m := members[0].(map[string]interface{})
+	if m["username"] != "gmuser" {
+		t.Fatalf("expected username gmuser, got %v", m["username"])
+	}
+
+	// ── My groups (user endpoint) ──
+	w = h.request("GET", "/api/v1/groups/mine", userToken, nil)
+	if w.Code != http.StatusOK {
+		t.Fatalf("my groups: want 200, got %d", w.Code)
+	}
+	var myResp map[string]interface{}
+	decode(w, &myResp)
+	myGroups := myResp["data"].([]interface{})
+	if len(myGroups) != 1 {
+		t.Fatalf("user should be in 1 group, got %d", len(myGroups))
+	}
+
+	// ── Idempotent add (no error) ──
+	w = h.request("POST", "/api/v1/admin/groups/"+group.ID+"/members", adminToken, map[string]interface{}{
+		"user_id": userID,
+	})
+	if w.Code != http.StatusOK {
+		t.Fatalf("idempotent add: want 200, got %d", w.Code)
+	}
+
+	// ── Remove member ──
+	w = h.request("DELETE", fmt.Sprintf("/api/v1/admin/groups/%s/members/%s", group.ID, userID), adminToken, nil)
+	if w.Code != http.StatusOK {
+		t.Fatalf("remove member: want 200, got %d: %s", w.Code, w.Body.String())
+	}
+
+	// Verify removed
+	w = h.request("GET", "/api/v1/admin/groups/"+group.ID+"/members", adminToken, nil)
+	decode(w, &memberResp)
+	members = memberResp["data"].([]interface{})
+	if len(members) != 0 {
+		t.Fatalf("expected 0 members after removal, got %d", len(members))
+	}
+}
+
+func TestGroupScopeValidation(t *testing.T) {
+	h := setupHarness(t)
+
+	_, adminToken := h.createAdminUser("gsadmin", "gsadmin@test.com")
+
+	// Team-scoped without team_id → 400
+	w := h.request("POST", "/api/v1/admin/groups", adminToken, map[string]interface{}{
+		"name":  "Bad Group",
+		"scope": "team",
+	})
+	if w.Code != http.StatusBadRequest {
+		t.Fatalf("team scope without team_id: want 400, got %d", w.Code)
+	}
+
+	// Global with team_id → 400
+	w = h.request("POST", "/api/v1/admin/groups", adminToken, map[string]interface{}{
+		"name":    "Bad Group",
+		"scope":   "global",
+		"team_id": "00000000-0000-0000-0000-000000000001",
+	})
+	if w.Code != http.StatusBadRequest {
+		t.Fatalf("global scope with team_id: want 400, got %d", w.Code)
+	}
+}
+
+func TestResourceGrants(t *testing.T) {
+	h := setupHarness(t)
+
+	_, adminToken := h.createAdminUser("rgadmin", "rgadmin@test.com")
+
+	// Create a group
+	w := h.request("POST", "/api/v1/admin/groups", adminToken, map[string]interface{}{
+		"name":  "Grantees",
+		"scope": "global",
+	})
+	var group models.Group
+	decode(w, &group)
+
+	// Create a persona (admin)
+	w = h.request("POST", "/api/v1/admin/presets", adminToken, map[string]interface{}{
+		"name":          "Test Bot",
+		"base_model_id": "test-model",
+		"scope":         "global",
+	})
+	if w.Code != http.StatusCreated {
+		t.Fatalf("create persona: want 201, got %d: %s", w.Code, w.Body.String())
+	}
+	var persona map[string]interface{}
+	decode(w, &persona)
+	personaID := persona["id"].(string)
+
+	// ── Get grant (no grant yet → default team_only) ──
+	w = h.request("GET", fmt.Sprintf("/api/v1/admin/grants/persona/%s", personaID), adminToken, nil)
+	if w.Code != http.StatusOK {
+		t.Fatalf("get grant: want 200, got %d", w.Code)
+	}
+	var grantResp map[string]interface{}
+	decode(w, &grantResp)
+	if grantResp["grant_scope"] != "team_only" {
+		t.Fatalf("default grant_scope should be team_only, got %v", grantResp["grant_scope"])
+	}
+
+	// ── Set grant: groups scope ──
+	w = h.request("PUT", fmt.Sprintf("/api/v1/admin/grants/persona/%s", personaID), adminToken, map[string]interface{}{
+		"grant_scope":    "groups",
+		"granted_groups": []string{group.ID},
+	})
+	if w.Code != http.StatusOK {
+		t.Fatalf("set grant: want 200, got %d: %s", w.Code, w.Body.String())
+	}
+
+	// ── Get grant (now groups) ──
+	w = h.request("GET", fmt.Sprintf("/api/v1/admin/grants/persona/%s", personaID), adminToken, nil)
+	decode(w, &grantResp)
+	if grantResp["grant_scope"] != "groups" {
+		t.Fatalf("grant_scope should be groups, got %v", grantResp["grant_scope"])
+	}
+
+	// ── Set grant: global scope ──
+	w = h.request("PUT", fmt.Sprintf("/api/v1/admin/grants/persona/%s", personaID), adminToken, map[string]interface{}{
+		"grant_scope": "global",
+	})
+	if w.Code != http.StatusOK {
+		t.Fatalf("set global grant: want 200, got %d: %s", w.Code, w.Body.String())
+	}
+
+	// ── Revoke: set back to team_only (deletes grant row) ──
+	w = h.request("PUT", fmt.Sprintf("/api/v1/admin/grants/persona/%s", personaID), adminToken, map[string]interface{}{
+		"grant_scope": "team_only",
+	})
+	if w.Code != http.StatusOK {
+		t.Fatalf("revoke grant: want 200, got %d: %s", w.Code, w.Body.String())
+	}
+
+	// ── Validation: groups scope without groups → 400 ──
+	w = h.request("PUT", fmt.Sprintf("/api/v1/admin/grants/persona/%s", personaID), adminToken, map[string]interface{}{
+		"grant_scope": "groups",
+	})
+	if w.Code != http.StatusBadRequest {
+		t.Fatalf("groups without list: want 400, got %d", w.Code)
+	}
+}
+
+func TestGroupBasedPersonaAccess(t *testing.T) {
+	h := setupHarness(t)
+
+	// Setup: admin + regular user (not on any team)
+	adminID, adminToken := h.createAdminUser("gpadmin", "gpadmin@test.com")
+	userID := database.SeedTestUser(h.t, "gpuser", "gpuser@test.com")
+	database.TestDB.Exec("UPDATE users SET is_active = true WHERE id = $1", userID)
+	userToken := makeToken(userID, "gpuser@test.com", "user")
+
+	// Create a team
+	w := h.request("POST", "/api/v1/admin/teams", adminToken, map[string]interface{}{
+		"name": "Secret Team",
+	})
+	var teamResp map[string]interface{}
+	decode(w, &teamResp)
+	teamID := teamResp["id"].(string)
+
+	// Create persona scoped to that team (user shouldn't see it without group access)
+	var personaID string
+	err := database.DB.QueryRow(`
+		INSERT INTO personas (name, base_model_id, scope, owner_id, created_by, is_active)
+		VALUES ('Secret Bot', 'test-model', 'team', $1, $2, true)
+		RETURNING id
+	`, teamID, adminID).Scan(&personaID)
+	if err != nil {
+		t.Fatalf("insert persona: %v", err)
+	}
+	if personaID == "" {
+		t.Fatal("personaID is empty after insert")
+	}
+
+	// ── User should NOT see team persona ──
+	w = h.request("GET", "/api/v1/presets", userToken, nil)
+	var presetsResp map[string]interface{}
+	decode(w, &presetsResp)
+	presets, _ := presetsResp["presets"].([]interface{})
+	for _, p := range presets {
+		pm := p.(map[string]interface{})
+		if pm["id"] == personaID {
+			t.Fatalf("user should NOT see team persona without group access")
+		}
+	}
+
+	// ── Create group + add user + grant persona ──
+	w = h.request("POST", "/api/v1/admin/groups", adminToken, map[string]interface{}{
+		"name":  "Secret Readers",
+		"scope": "global",
+	})
+	var group models.Group
+	decode(w, &group)
+
+	w = h.request("POST", "/api/v1/admin/groups/"+group.ID+"/members", adminToken, map[string]interface{}{
+		"user_id": userID,
+	})
+
+	w = h.request("PUT", fmt.Sprintf("/api/v1/admin/grants/persona/%s", personaID), adminToken, map[string]interface{}{
+		"grant_scope":    "groups",
+		"granted_groups": []string{group.ID},
+	})
+	if w.Code != http.StatusOK {
+		t.Fatalf("set grant: want 200, got %d: %s", w.Code, w.Body.String())
+	}
+
+	// Diagnostic: verify grant row exists
+	var grantCount int
+	database.DB.QueryRow(`SELECT COUNT(*) FROM resource_grants WHERE resource_type = 'persona' AND resource_id = $1`, personaID).Scan(&grantCount)
+	if grantCount == 0 {
+		t.Fatal("DIAG: resource_grant row missing after SET")
+	}
+
+	// Diagnostic: verify group membership
+	var memberCount int
+	database.DB.QueryRow(`SELECT COUNT(*) FROM group_members WHERE group_id = $1 AND user_id = $2`, group.ID, userID).Scan(&memberCount)
+	if memberCount == 0 {
+		t.Fatal("DIAG: group_members row missing")
+	}
+
+	// Diagnostic: verify persona exists
+	var personaExists bool
+	database.DB.QueryRow(`SELECT EXISTS(SELECT 1 FROM personas WHERE id = $1 AND is_active = true)`, personaID).Scan(&personaExists)
+	if !personaExists {
+		t.Fatal("DIAG: persona not found or not active")
+	}
+
+	// Diagnostic: run the subquery directly
+	var subqCount int
+	database.DB.QueryRow(`
+		SELECT COUNT(*) FROM resource_grants rg
+		WHERE rg.resource_type = 'persona'
+		  AND (
+			rg.grant_scope = 'global'
+			OR (rg.grant_scope = 'groups'
+			    AND EXISTS (
+			        SELECT 1 FROM group_members gm
+			        WHERE gm.user_id = $1
+			          AND gm.group_id = ANY(rg.granted_groups)
+			    ))
+		  )
+	`, userID).Scan(&subqCount)
+	t.Logf("DIAG: grant_count=%d member_count=%d persona_exists=%v subquery_matches=%d personaID=%s groupID=%s userID=%s",
+		grantCount, memberCount, personaExists, subqCount, personaID, group.ID, userID)
+
+	// ── User should NOW see team persona via group grant ──
+	w = h.request("GET", "/api/v1/presets", userToken, nil)
+	if w.Code != http.StatusOK {
+		t.Fatalf("list presets: want 200, got %d: %s", w.Code, w.Body.String())
+	}
+	decode(w, &presetsResp)
+	presets, _ = presetsResp["presets"].([]interface{})
+	found := false
+	for _, p := range presets {
+		pm := p.(map[string]interface{})
+		if pm["id"] == personaID {
+			found = true
+			break
+		}
+	}
+	if !found {
+		t.Fatalf("user should see team persona after group grant, but didn't find it in %d presets (response: %s)", len(presets), w.Body.String())
+	}
+
+	// ── Remove user from group → should lose access ──
+	w = h.request("DELETE", fmt.Sprintf("/api/v1/admin/groups/%s/members/%s", group.ID, userID), adminToken, nil)
+
+	w = h.request("GET", "/api/v1/presets", userToken, nil)
+	decode(w, &presetsResp)
+	presets, _ = presetsResp["presets"].([]interface{})
+	for _, p := range presets {
+		pm := p.(map[string]interface{})
+		if pm["id"] == personaID {
+			t.Fatalf("user should NOT see persona after group removal")
+		}
+	}
+}
+
diff --git a/server/main.go b/server/main.go
index 224556f..5e39c76 100644
--- a/server/main.go
+++ b/server/main.go
@@ -344,6 +344,10 @@ func main() {
 			teams := handlers.NewTeamHandler(keyResolver)
 			protected.GET("/teams/mine", teams.MyTeams)
 
+			// Groups (user: my groups — v0.16.0)
+			groupH := handlers.NewGroupHandler(stores)
+			protected.GET("/groups/mine", groupH.MyGroups)
+
 			// Team admin self-service
 			teamScoped := protected.Group("/teams/:teamId")
 			teamScoped.Use(middleware.RequireTeamAdmin())
@@ -354,6 +358,9 @@ func main() {
 				teamScoped.DELETE("/members/:memberId", teams.RemoveMember)
 				teamScoped.GET("/models", teams.ListAvailableModels)
 
+				// Team groups (team admins manage team-scoped groups)
+				teamScoped.GET("/groups", groupH.ListTeamGroups)
+
 				// Team providers
 				teamScoped.GET("/providers", teams.ListTeamProviders)
 				teamScoped.POST("/providers", teams.CreateTeamProvider)
@@ -455,6 +462,22 @@ func main() {
 			admin.GET("/audit", adm.ListAuditLog)
 			admin.GET("/audit/actions", adm.ListAuditActions)
 
+			// Groups (admin — v0.16.0)
+			groupAdm := handlers.NewGroupHandler(stores)
+			admin.GET("/groups", groupAdm.ListGroups)
+			admin.POST("/groups", groupAdm.CreateGroup)
+			admin.GET("/groups/:id", groupAdm.GetGroup)
+			admin.PUT("/groups/:id", groupAdm.UpdateGroup)
+			admin.DELETE("/groups/:id", groupAdm.DeleteGroup)
+			admin.GET("/groups/:id/members", groupAdm.ListMembers)
+			admin.POST("/groups/:id/members", groupAdm.AddMember)
+			admin.DELETE("/groups/:id/members/:userId", groupAdm.RemoveMember)
+
+			// Resource Grants (admin — v0.16.0)
+			admin.GET("/grants/:type/:id", groupAdm.GetResourceGrant)
+			admin.PUT("/grants/:type/:id", groupAdm.SetResourceGrant)
+			admin.DELETE("/grants/:type/:id", groupAdm.DeleteResourceGrant)
+
 			// Model Roles
 			rolesH := handlers.NewRolesHandler(stores, roleResolver)
 			admin.GET("/roles", rolesH.ListRoles)
diff --git a/server/models/models.go b/server/models/models.go
index 32951a1..7aaa542 100644
--- a/server/models/models.go
+++ b/server/models/models.go
@@ -623,6 +623,60 @@ func Float64Ptr(f float64) *float64 { return &f }
 func IntPtr(i int) *int             { return &i }
 func BoolPtr(b bool) *bool          { return &b }
 
+// =========================================
+// GROUPS (v0.16.0)
+// =========================================
+
+// Group scope constants (reuses ScopeGlobal, ScopeTeam from above)
+
+// ResourceType constants for resource_grants
+const (
+	ResourceTypePersona       = "persona"
+	ResourceTypeKnowledgeBase = "knowledge_base"
+)
+
+// GrantScope constants for resource_grants
+const (
+	GrantScopeTeamOnly = "team_only"
+	GrantScopeGlobal   = "global"
+	GrantScopeGroups   = "groups"
+)
+
+// Group is an access-control list. Decouples resource visibility from teams.
+type Group struct {
+	BaseModel
+	Name        string  `json:"name" db:"name"`
+	Description string  `json:"description" db:"description"`
+	Scope       string  `json:"scope" db:"scope"`     // global, team
+	TeamID      *string `json:"team_id,omitempty" db:"team_id"`
+	CreatedBy   string  `json:"created_by" db:"created_by"`
+	MemberCount int     `json:"member_count,omitempty"` // computed, not a DB column
+}
+
+// GroupMember links a user to a group.
+type GroupMember struct {
+	ID      string    `json:"id" db:"id"`
+	GroupID string    `json:"group_id" db:"group_id"`
+	UserID  string    `json:"user_id" db:"user_id"`
+	AddedBy string    `json:"added_by" db:"added_by"`
+	AddedAt time.Time `json:"added_at" db:"added_at"`
+	// Joined fields from users table (for list responses)
+	Username    string `json:"username,omitempty"`
+	Email       string `json:"email,omitempty"`
+	DisplayName string `json:"display_name,omitempty"`
+}
+
+// ResourceGrant controls who can USE a resource (personas, KBs) via groups.
+// One row per resource. Not to be confused with persona_grants (what a Persona can DO).
+type ResourceGrant struct {
+	BaseModel
+	ResourceType  string   `json:"resource_type" db:"resource_type"`
+	ResourceID    string   `json:"resource_id" db:"resource_id"`
+	GrantScope    string   `json:"grant_scope" db:"grant_scope"`
+	GrantedGroups []string `json:"granted_groups" db:"granted_groups"` // UUID array
+	CreatedBy     string   `json:"created_by" db:"created_by"`
+}
+
 // ── Knowledge Bases ────────────────────────────
 
 // KnowledgeBase is a named collection of documents with vector embeddings.
diff --git a/server/store/interfaces.go b/server/store/interfaces.go
index 05d9076..fb351af 100644
--- a/server/store/interfaces.go
+++ b/server/store/interfaces.go
@@ -35,6 +35,8 @@ type Stores struct {
 	Extensions    ExtensionStore
 	Attachments   AttachmentStore
 	KnowledgeBases KnowledgeBaseStore
+	Groups         GroupStore
+	ResourceGrants ResourceGrantStore
 }
 
 // =========================================
@@ -401,6 +403,44 @@ type KnowledgeBaseStore interface {
 	UpdateStats(ctx context.Context, kbID string) error
 }
 
+// =========================================
+// GROUP STORE (v0.16.0)
+// =========================================
+
+type GroupStore interface {
+	Create(ctx context.Context, g *models.Group) error
+	GetByID(ctx context.Context, id string) (*models.Group, error)
+	Update(ctx context.Context, id string, name, description *string) error
+	Delete(ctx context.Context, id string) error
+
+	// Scoped listing
+	ListAll(ctx context.Context) ([]models.Group, error)           // admin
+	ListForTeam(ctx context.Context, teamID string) ([]models.Group, error) // team admin
+	ListForUser(ctx context.Context, userID string) ([]models.Group, error) // groups I belong to
+
+	// Members
+	AddMember(ctx context.Context, groupID, userID, addedBy string) error
+	RemoveMember(ctx context.Context, groupID, userID string) error
+	ListMembers(ctx context.Context, groupID string) ([]models.GroupMember, error)
+	IsMember(ctx context.Context, groupID, userID string) (bool, error)
+
+	// For access resolution: returns group IDs a user belongs to
+	GetUserGroupIDs(ctx context.Context, userID string) ([]string, error)
+}
+
+// =========================================
+// RESOURCE GRANT STORE (v0.16.0)
+// =========================================
+
+type ResourceGrantStore interface {
+	Set(ctx context.Context, grant *models.ResourceGrant) error
+	Get(ctx context.Context, resourceType, resourceID string) (*models.ResourceGrant, error)
+	Delete(ctx context.Context, resourceType, resourceID string) error
+
+	// Access check: does userID have group-based access to this resource?
+	UserHasGroupAccess(ctx context.Context, userID, resourceType, resourceID string) (bool, error)
+}
+
 // =========================================
 // SHARED TYPES
 // =========================================
diff --git a/server/store/postgres/groups.go b/server/store/postgres/groups.go
new file mode 100644
index 0000000..9d3c22b
--- /dev/null
+++ b/server/store/postgres/groups.go
@@ -0,0 +1,206 @@
+package postgres
+
+import (
+	"context"
+	"database/sql"
+	"fmt"
+
+	"git.gobha.me/xcaliber/chat-switchboard/models"
+)
+
+// ── GroupStore ──────────────────────────────
+
+type GroupStore struct{}
+
+func NewGroupStore() *GroupStore { return &GroupStore{} }
+
+func (s *GroupStore) Create(ctx context.Context, g *models.Group) error {
+	return DB.QueryRowContext(ctx, `
+		INSERT INTO groups (name, description, scope, team_id, created_by)
+		VALUES ($1, $2, $3, $4, $5)
+		RETURNING id, created_at, updated_at`,
+		g.Name, g.Description, g.Scope,
+		models.NullString(g.TeamID), g.CreatedBy,
+	).Scan(&g.ID, &g.CreatedAt, &g.UpdatedAt)
+}
+
+func (s *GroupStore) GetByID(ctx context.Context, id string) (*models.Group, error) {
+	var g models.Group
+	var teamID sql.NullString
+	err := DB.QueryRowContext(ctx, `
+		SELECT g.id, g.name, g.description, g.scope, g.team_id, g.created_by,
+		       g.created_at, g.updated_at,
+		       (SELECT COUNT(*) FROM group_members WHERE group_id = g.id) AS member_count
+		FROM groups g WHERE g.id = $1`, id).Scan(
+		&g.ID, &g.Name, &g.Description, &g.Scope, &teamID, &g.CreatedBy,
+		&g.CreatedAt, &g.UpdatedAt, &g.MemberCount,
+	)
+	if err != nil {
+		return nil, err
+	}
+	g.TeamID = NullableStringPtr(teamID)
+	return &g, nil
+}
+
+func (s *GroupStore) Update(ctx context.Context, id string, name, description *string) error {
+	b := NewUpdate("groups")
+	if name != nil {
+		b.Set("name", *name)
+	}
+	if description != nil {
+		b.Set("description", *description)
+	}
+	if !b.HasSets() {
+		return nil
+	}
+	b.Where("id", id)
+	res, err := b.Exec(DB)
+	if err != nil {
+		return err
+	}
+	if n, _ := res.RowsAffected(); n == 0 {
+		return sql.ErrNoRows
+	}
+	return nil
+}
+
+func (s *GroupStore) Delete(ctx context.Context, id string) error {
+	res, err := DB.ExecContext(ctx, "DELETE FROM groups WHERE id = $1", id)
+	if err != nil {
+		return err
+	}
+	if n, _ := res.RowsAffected(); n == 0 {
+		return sql.ErrNoRows
+	}
+	return nil
+}
+
+// ── Scoped Listing ──────────────────────────
+
+func (s *GroupStore) ListAll(ctx context.Context) ([]models.Group, error) {
+	return queryGroups(ctx, `
+		SELECT g.id, g.name, g.description, g.scope, g.team_id, g.created_by,
+		       g.created_at, g.updated_at,
+		       (SELECT COUNT(*) FROM group_members WHERE group_id = g.id)
+		FROM groups g
+		ORDER BY g.scope, g.name`)
+}
+
+func (s *GroupStore) ListForTeam(ctx context.Context, teamID string) ([]models.Group, error) {
+	return queryGroups(ctx, `
+		SELECT g.id, g.name, g.description, g.scope, g.team_id, g.created_by,
+		       g.created_at, g.updated_at,
+		       (SELECT COUNT(*) FROM group_members WHERE group_id = g.id)
+		FROM groups g
+		WHERE g.scope = 'team' AND g.team_id = $1
+		ORDER BY g.name`, teamID)
+}
+
+func (s *GroupStore) ListForUser(ctx context.Context, userID string) ([]models.Group, error) {
+	return queryGroups(ctx, `
+		SELECT g.id, g.name, g.description, g.scope, g.team_id, g.created_by,
+		       g.created_at, g.updated_at,
+		       (SELECT COUNT(*) FROM group_members WHERE group_id = g.id)
+		FROM groups g
+		WHERE g.id IN (SELECT group_id FROM group_members WHERE user_id = $1)
+		ORDER BY g.scope, g.name`, userID)
+}
+
+// ── Members ─────────────────────────────────
+
+func (s *GroupStore) AddMember(ctx context.Context, groupID, userID, addedBy string) error {
+	_, err := DB.ExecContext(ctx, `
+		INSERT INTO group_members (group_id, user_id, added_by)
+		VALUES ($1, $2, $3)
+		ON CONFLICT (group_id, user_id) DO NOTHING`,
+		groupID, userID, addedBy)
+	return err
+}
+
+func (s *GroupStore) RemoveMember(ctx context.Context, groupID, userID string) error {
+	res, err := DB.ExecContext(ctx,
+		"DELETE FROM group_members WHERE group_id = $1 AND user_id = $2",
+		groupID, userID)
+	if err != nil {
+		return err
+	}
+	if n, _ := res.RowsAffected(); n == 0 {
+		return sql.ErrNoRows
+	}
+	return nil
+}
+
+func (s *GroupStore) ListMembers(ctx context.Context, groupID string) ([]models.GroupMember, error) {
+	rows, err := DB.QueryContext(ctx, `
+		SELECT gm.id, gm.group_id, gm.user_id, gm.added_by, gm.added_at,
+		       u.username, u.email, COALESCE(u.display_name, '')
+		FROM group_members gm
+		JOIN users u ON u.id = gm.user_id
+		WHERE gm.group_id = $1
+		ORDER BY u.username`, groupID)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	var result []models.GroupMember
+	for rows.Next() {
+		var m models.GroupMember
+		if err := rows.Scan(&m.ID, &m.GroupID, &m.UserID, &m.AddedBy, &m.AddedAt,
+			&m.Username, &m.Email, &m.DisplayName); err != nil {
+			return nil, err
+		}
+		result = append(result, m)
+	}
+	return result, rows.Err()
+}
+
+func (s *GroupStore) IsMember(ctx context.Context, groupID, userID string) (bool, error) {
+	var exists bool
+	err := DB.QueryRowContext(ctx, `
+		SELECT EXISTS(SELECT 1 FROM group_members WHERE group_id = $1 AND user_id = $2)`,
+		groupID, userID).Scan(&exists)
+	return exists, err
+}
+
+func (s *GroupStore) GetUserGroupIDs(ctx context.Context, userID string) ([]string, error) {
+	rows, err := DB.QueryContext(ctx,
+		"SELECT group_id FROM group_members WHERE user_id = $1", userID)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	var ids []string
+	for rows.Next() {
+		var id string
+		if err := rows.Scan(&id); err != nil {
+			return nil, err
+		}
+		ids = append(ids, id)
+	}
+	return ids, rows.Err()
+}
+
+// ── Scanners ────────────────────────────────
+
+func queryGroups(ctx context.Context, q string, args ...interface{}) ([]models.Group, error) {
+	rows, err := DB.QueryContext(ctx, q, args...)
+	if err != nil {
+		return nil, fmt.Errorf("queryGroups: %w", err)
+	}
+	defer rows.Close()
+
+	var result []models.Group
+	for rows.Next() {
+		var g models.Group
+		var teamID sql.NullString
+		if err := rows.Scan(&g.ID, &g.Name, &g.Description, &g.Scope, &teamID,
+			&g.CreatedBy, &g.CreatedAt, &g.UpdatedAt, &g.MemberCount); err != nil {
+			return nil, err
+		}
+		g.TeamID = NullableStringPtr(teamID)
+		result = append(result, g)
+	}
+	return result, rows.Err()
+}
diff --git a/server/store/postgres/knowledge_bases.go b/server/store/postgres/knowledge_bases.go
index 0a0ca15..674d892 100644
--- a/server/store/postgres/knowledge_bases.go
+++ b/server/store/postgres/knowledge_bases.go
@@ -68,7 +68,7 @@ func (s *KnowledgeBaseStore) Delete(ctx context.Context, id string) error {
 // ── Scoped Listing ──────────────────────────────
 
 func (s *KnowledgeBaseStore) ListForUser(ctx context.Context, userID string, teamIDs []string) ([]models.KnowledgeBase, error) {
-	// User can see: global + their teams + personal.
+	// User can see: global + their teams + personal + group-granted.
 	q := `
 		SELECT id, name, description, scope, owner_id, team_id, embedding_config,
 			document_count, chunk_count, total_bytes, status, created_at, updated_at
@@ -83,6 +83,23 @@ func (s *KnowledgeBaseStore) ListForUser(ctx context.Context, userID string, tea
 		args = append(args, pq.Array(teamIDs))
 	}
 
+	// Group-granted KBs
+	q += fmt.Sprintf(`
+		   OR id IN (
+			SELECT rg.resource_id FROM resource_grants rg
+			WHERE rg.resource_type = 'knowledge_base'
+			  AND (
+				rg.grant_scope = 'global'
+				OR (rg.grant_scope = 'groups'
+				    AND EXISTS (
+				        SELECT 1 FROM group_members gm
+				        WHERE gm.user_id = $%d
+				          AND gm.group_id = ANY(rg.granted_groups)
+				    ))
+			  )
+		)`, len(args)+1)
+	args = append(args, userID)
+
 	q += ` ORDER BY name`
 	return queryKBs(ctx, q, args...)
 }
diff --git a/server/store/postgres/persona.go b/server/store/postgres/persona.go
index 6d5a38f..04f14a7 100644
--- a/server/store/postgres/persona.go
+++ b/server/store/postgres/persona.go
@@ -100,7 +100,7 @@ func (s *PersonaStore) Delete(ctx context.Context, id string) error {
 }
 
 // ListForUser returns all Personas visible to a user:
-// global active + team-scoped (for user's teams) + personal + shared.
+// global active + team-scoped (for user's teams) + personal + shared + group-granted.
 func (s *PersonaStore) ListForUser(ctx context.Context, userID string) ([]models.Persona, error) {
 	rows, err := DB.QueryContext(ctx,
 		fmt.Sprintf(`SELECT %s FROM personas WHERE is_active = true AND (
@@ -110,6 +110,19 @@ func (s *PersonaStore) ListForUser(ctx context.Context, userID string) ([]models
 				SELECT team_id FROM team_members WHERE user_id = $1
 			))
 			OR (scope = 'personal' AND is_shared = true)
+			OR id IN (
+				SELECT rg.resource_id FROM resource_grants rg
+				WHERE rg.resource_type = 'persona'
+				  AND (
+					rg.grant_scope = 'global'
+					OR (rg.grant_scope = 'groups'
+					    AND EXISTS (
+					        SELECT 1 FROM group_members gm
+					        WHERE gm.user_id = $1
+					          AND gm.group_id = ANY(rg.granted_groups)
+					    ))
+				  )
+			)
 		) ORDER BY scope, name`, personaCols), userID)
 	if err != nil {
 		return nil, err
@@ -235,6 +248,20 @@ func (s *PersonaStore) UserCanAccess(ctx context.Context, userID, personaID stri
 					SELECT team_id FROM team_members WHERE user_id = $1
 				))
 				OR (scope = 'personal' AND is_shared = true)
+				OR id IN (
+					SELECT rg.resource_id FROM resource_grants rg
+					WHERE rg.resource_type = 'persona'
+					  AND rg.resource_id = $2
+					  AND (
+						rg.grant_scope = 'global'
+						OR (rg.grant_scope = 'groups'
+						    AND EXISTS (
+						        SELECT 1 FROM group_members gm
+						        WHERE gm.user_id = $1
+						          AND gm.group_id = ANY(rg.granted_groups)
+						    ))
+					  )
+				)
 			)
 		)`, userID, personaID).Scan(&exists)
 	return exists, err
diff --git a/server/store/postgres/resource_grants.go b/server/store/postgres/resource_grants.go
new file mode 100644
index 0000000..7f9f20a
--- /dev/null
+++ b/server/store/postgres/resource_grants.go
@@ -0,0 +1,95 @@
+package postgres
+
+import (
+	"context"
+	"database/sql"
+
+	"git.gobha.me/xcaliber/chat-switchboard/models"
+
+	"github.com/lib/pq"
+)
+
+// ── ResourceGrantStore ──────────────────────
+
+type ResourceGrantStore struct{}
+
+func NewResourceGrantStore() *ResourceGrantStore { return &ResourceGrantStore{} }
+
+// Set creates or replaces the grant for a resource (upsert on unique resource_type+resource_id).
+func (s *ResourceGrantStore) Set(ctx context.Context, grant *models.ResourceGrant) error {
+	// Coalesce nil to empty slice — pq.Array(nil) produces SQL NULL, but column expects array.
+	groups := grant.GrantedGroups
+	if groups == nil {
+		groups = []string{}
+	}
+	return DB.QueryRowContext(ctx, `
+		INSERT INTO resource_grants (resource_type, resource_id, grant_scope, granted_groups, created_by)
+		VALUES ($1, $2, $3, $4, $5)
+		ON CONFLICT (resource_type, resource_id) DO UPDATE SET
+			grant_scope    = EXCLUDED.grant_scope,
+			granted_groups = EXCLUDED.granted_groups,
+			created_by     = EXCLUDED.created_by
+		RETURNING id, created_at, updated_at`,
+		grant.ResourceType, grant.ResourceID, grant.GrantScope,
+		pq.Array(groups), grant.CreatedBy,
+	).Scan(&grant.ID, &grant.CreatedAt, &grant.UpdatedAt)
+}
+
+// Get retrieves the grant for a specific resource.
+func (s *ResourceGrantStore) Get(ctx context.Context, resourceType, resourceID string) (*models.ResourceGrant, error) {
+	var rg models.ResourceGrant
+	err := DB.QueryRowContext(ctx, `
+		SELECT id, resource_type, resource_id, grant_scope, granted_groups, created_by,
+		       created_at, updated_at
+		FROM resource_grants
+		WHERE resource_type = $1 AND resource_id = $2`,
+		resourceType, resourceID,
+	).Scan(&rg.ID, &rg.ResourceType, &rg.ResourceID, &rg.GrantScope,
+		pq.Array(&rg.GrantedGroups), &rg.CreatedBy,
+		&rg.CreatedAt, &rg.UpdatedAt)
+	if err != nil {
+		return nil, err
+	}
+	return &rg, nil
+}
+
+// Delete removes the grant for a resource.
+func (s *ResourceGrantStore) Delete(ctx context.Context, resourceType, resourceID string) error {
+	res, err := DB.ExecContext(ctx,
+		"DELETE FROM resource_grants WHERE resource_type = $1 AND resource_id = $2",
+		resourceType, resourceID)
+	if err != nil {
+		return err
+	}
+	if n, _ := res.RowsAffected(); n == 0 {
+		return sql.ErrNoRows
+	}
+	return nil
+}
+
+// UserHasGroupAccess checks whether a user has group-based access to a resource.
+// Returns true if:
+//   - The resource has grant_scope='global', OR
+//   - The resource has grant_scope='groups' and the user is in at least one
+//     of the granted_groups.
+func (s *ResourceGrantStore) UserHasGroupAccess(ctx context.Context, userID, resourceType, resourceID string) (bool, error) {
+	var has bool
+	err := DB.QueryRowContext(ctx, `
+		SELECT EXISTS(
+			SELECT 1 FROM resource_grants rg
+			WHERE rg.resource_type = $1
+			  AND rg.resource_id   = $2
+			  AND (
+				rg.grant_scope = 'global'
+				OR (
+					rg.grant_scope = 'groups'
+					AND EXISTS (
+						SELECT 1 FROM group_members gm
+						WHERE gm.user_id = $3
+						  AND gm.group_id = ANY(rg.granted_groups)
+					)
+				)
+			  )
+		)`, resourceType, resourceID, userID).Scan(&has)
+	return has, err
+}
diff --git a/server/store/postgres/stores.go b/server/store/postgres/stores.go
index 0089c71..b80804a 100644
--- a/server/store/postgres/stores.go
+++ b/server/store/postgres/stores.go
@@ -28,5 +28,7 @@ func NewStores(db *sql.DB) store.Stores {
 		Extensions:   NewExtensionStore(),
 		Attachments:  NewAttachmentStore(),
 		KnowledgeBases: NewKnowledgeBaseStore(),
+		Groups:         NewGroupStore(),
+		ResourceGrants: NewResourceGrantStore(),
 	}
 }
diff --git a/src/index.html b/src/index.html
index 5929f25..8791be7 100644
--- a/src/index.html
+++ b/src/index.html
@@ -516,6 +516,7 @@
                 <button class="admin-tab" data-ttab="usage" onclick="UI.switchTeamTab('usage')">Usage</button>
                 <button class="admin-tab" data-ttab="activity" onclick="UI.switchTeamTab('activity')">Activity</button>
                 <button class="admin-tab" data-ttab="knowledge" onclick="UI.switchTeamTab('knowledge')">Knowledge</button>
+                <button class="admin-tab" data-ttab="groups" onclick="UI.switchTeamTab('groups')">Groups</button>
             </div>
             <div class="modal-body">
                 <!-- Members tab -->
@@ -578,6 +579,11 @@
                 <div class="team-tab-content" id="teamTabKnowledge" style="display:none">
                     <div id="teamKBContent"></div>
                 </div>
+                <!-- Groups tab -->
+                <div class="team-tab-content" id="teamTabGroups" style="display:none">
+                    <p class="text-muted" style="font-size:12px;margin:0 0 8px">Groups assigned to this team. Contact a system admin to create or modify groups.</p>
+                    <div id="settingsTeamGroups"></div>
+                </div>
             </div>
         </div>
     </div>
@@ -651,6 +657,43 @@
                     <div id="adminMemberList"></div>
                 </div>
             </div>
+            <div class="admin-section-content" id="adminGroupsTab" style="display:none">
+                <div class="admin-toolbar">
+                    <button class="btn-small btn-primary" id="adminAddGroupBtn">+ New Group</button>
+                </div>
+                <div id="adminAddGroupForm" style="display:none" class="admin-inline-form">
+                    <div class="form-row">
+                        <div class="form-group"><label>Group Name</label><input type="text" id="adminGroupName" placeholder="Engineering"></div>
+                        <div class="form-group"><label>Scope</label>
+                            <select id="adminGroupScope">
+                                <option value="global">Global</option>
+                                <option value="team">Team</option>
+                            </select>
+                        </div>
+                    </div>
+                    <div class="form-group" id="adminGroupTeamRow" style="display:none">
+                        <label>Team</label><select id="adminGroupTeam"><option value="">Select team...</option></select>
+                    </div>
+                    <div class="form-group"><label>Description</label><input type="text" id="adminGroupDesc" placeholder="Access group for engineering resources"></div>
+                    <div class="form-row"><button class="btn-small btn-primary" id="adminCreateGroupBtn">Create</button><button class="btn-small" id="adminCancelGroupBtn">Cancel</button></div>
+                </div>
+                <div id="adminGroupList"></div>
+                <div id="adminGroupDetail" style="display:none">
+                    <button class="notes-back-btn" id="adminGroupBackBtn">← Back to groups</button>
+                    <h3 id="adminGroupDetailName" style="margin:8px 0 4px;font-size:15px"></h3>
+                    <p id="adminGroupDetailMeta" class="text-muted" style="font-size:12px;margin:0 0 12px"></p>
+                    <div class="admin-toolbar">
+                        <button class="btn-small btn-primary" id="adminAddGroupMemberBtn">+ Add Member</button>
+                    </div>
+                    <div id="adminAddGroupMemberForm" style="display:none" class="admin-inline-form">
+                        <div class="form-row">
+                            <div class="form-group"><label>User</label><select id="adminGroupMemberUser"></select></div>
+                        </div>
+                        <div class="form-row"><button class="btn-small btn-primary" id="adminAddGroupMemberSubmit">Add</button><button class="btn-small" id="adminCancelGroupMemberBtn">Cancel</button></div>
+                    </div>
+                    <div id="adminGroupMemberList"></div>
+                </div>
+            </div>
             <div class="admin-section-content" id="adminRolesTab" style="display:none">
                 <p style="color:var(--text-muted);margin:0 0 12px">Configure system model roles. Each role has a primary and optional fallback model.</p>
                 <div id="adminRolesContent">
diff --git a/src/js/admin-handlers.js b/src/js/admin-handlers.js
index 20f9f64..9081420 100644
--- a/src/js/admin-handlers.js
+++ b/src/js/admin-handlers.js
@@ -400,6 +400,42 @@ async function settingsDeleteTeamPreset(teamId, presetId, name) {
 
 // ── Team Provider handlers — now managed by UI primitives in ui-settings.js ──
 
+// ── Group Actions ───────────────────────────
+
+async function deleteGroup(id, name) {
+    if (!await showConfirm(`Delete group "${name}"? Members will lose access to any resources granted via this group.`)) return;
+    try { await API.adminDeleteGroup(id); UI.toast('Group deleted'); await UI.loadAdminGroups(); }
+    catch (e) { UI.toast(e.message, 'error'); }
+}
+
+async function removeGroupMember(groupId, userId, label) {
+    if (!await showConfirm(`Remove ${label} from group?`)) return;
+    try {
+        await API.adminRemoveGroupMember(groupId, userId);
+        UI.toast('Member removed');
+        await UI.loadGroupMembers(groupId);
+    } catch (e) { UI.toast(e.message, 'error'); }
+}
+
+async function saveGrant(resourceType, resourceId) {
+    const scopeSel = document.getElementById(`grantScope_${resourceId}`);
+    if (!scopeSel) return;
+    const scope = scopeSel.value;
+    const groupsDiv = document.getElementById(`grantGroups_${resourceId}`);
+    const selectedGroups = [...(groupsDiv?.querySelectorAll('.grant-group-cb:checked') || [])].map(cb => cb.value);
+
+    if (scope === 'groups' && selectedGroups.length === 0) {
+        return UI.toast('Select at least one group', 'error');
+    }
+
+    try {
+        await API.adminSetGrant(resourceType, resourceId, scope, selectedGroups);
+        // Remove the picker
+        document.querySelectorAll('.grant-picker-active').forEach(el => el.remove());
+        UI.toast(scope === 'team_only' ? 'Access reverted to team only' : `Access set to ${scope}`);
+    } catch (e) { UI.toast(e.message, 'error'); }
+}
+
 // ── Admin Listeners (extracted from initListeners) ──
 
 function _initAdminListeners() {
@@ -509,6 +545,66 @@ function _initAdminListeners() {
         } catch (e) { UI.toast(e.message, 'error'); }
     });
 
+    // ── Group management ────────────────────────
+    document.getElementById('adminAddGroupBtn')?.addEventListener('click', async () => {
+        document.getElementById('adminAddGroupForm').style.display = '';
+        document.getElementById('adminGroupName').focus();
+        // Populate team dropdown
+        try {
+            const resp = await API.adminListTeams();
+            const teams = (resp.data || []).filter(t => t.is_active);
+            const sel = document.getElementById('adminGroupTeam');
+            sel.innerHTML = '<option value="">Select team...</option>' +
+                teams.map(t => `<option value="${t.id}">${esc(t.name)}</option>`).join('');
+        } catch (e) { /* proceed without teams */ }
+    });
+    document.getElementById('adminGroupScope')?.addEventListener('change', function() {
+        document.getElementById('adminGroupTeamRow').style.display = this.value === 'team' ? '' : 'none';
+    });
+    document.getElementById('adminCancelGroupBtn')?.addEventListener('click', () => {
+        document.getElementById('adminAddGroupForm').style.display = 'none';
+        document.getElementById('adminGroupName').value = '';
+        document.getElementById('adminGroupDesc').value = '';
+    });
+    document.getElementById('adminCreateGroupBtn')?.addEventListener('click', async () => {
+        const name = document.getElementById('adminGroupName').value.trim();
+        const desc = document.getElementById('adminGroupDesc').value.trim();
+        const scope = document.getElementById('adminGroupScope').value;
+        const teamId = scope === 'team' ? document.getElementById('adminGroupTeam').value : null;
+        if (!name) return UI.toast('Group name required', 'error');
+        if (scope === 'team' && !teamId) return UI.toast('Select a team for team-scoped groups', 'error');
+        try {
+            await API.adminCreateGroup(name, desc, scope, teamId);
+            document.getElementById('adminAddGroupForm').style.display = 'none';
+            document.getElementById('adminGroupName').value = '';
+            document.getElementById('adminGroupDesc').value = '';
+            UI.toast('Group created');
+            await UI.loadAdminGroups(true);
+        } catch (e) { UI.toast(e.message, 'error'); }
+    });
+    document.getElementById('adminGroupBackBtn')?.addEventListener('click', () => {
+        document.getElementById('adminGroupDetail').style.display = 'none';
+        document.getElementById('adminGroupList').style.display = '';
+        UI.loadAdminGroups(true);
+    });
+    document.getElementById('adminAddGroupMemberBtn')?.addEventListener('click', async () => {
+        document.getElementById('adminAddGroupMemberForm').style.display = '';
+        await UI.loadGroupMemberDropdown(UI._groupEditId);
+    });
+    document.getElementById('adminCancelGroupMemberBtn')?.addEventListener('click', () => {
+        document.getElementById('adminAddGroupMemberForm').style.display = 'none';
+    });
+    document.getElementById('adminAddGroupMemberSubmit')?.addEventListener('click', async () => {
+        const userId = document.getElementById('adminGroupMemberUser').value;
+        if (!userId) return UI.toast('Select a user', 'error');
+        try {
+            await API.adminAddGroupMember(UI._groupEditId, userId);
+            document.getElementById('adminAddGroupMemberForm').style.display = 'none';
+            UI.toast('Member added');
+            await UI.loadGroupMembers(UI._groupEditId);
+        } catch (e) { UI.toast(e.message, 'error'); }
+    });
+
     // ── Extension management ────────────────────
     document.getElementById('adminInstallExtBtn')?.addEventListener('click', () => {
         document.getElementById('adminInstallExtForm').style.display = '';
diff --git a/src/js/api.js b/src/js/api.js
index 7021331..f9e5349 100644
--- a/src/js/api.js
+++ b/src/js/api.js
@@ -413,6 +413,30 @@ const API = {
     adminUpdateMember(teamId, memberId, role) { return this._put(`/api/v1/admin/teams/${teamId}/members/${memberId}`, { role }); },
     adminRemoveMember(teamId, memberId) { return this._del(`/api/v1/admin/teams/${teamId}/members/${memberId}`); },
 
+    // ── Admin Groups ────────────────────────
+    adminListGroups() { return this._get('/api/v1/admin/groups'); },
+    adminCreateGroup(name, description, scope, teamId) {
+        const body = { name, description, scope };
+        if (teamId) body.team_id = teamId;
+        return this._post('/api/v1/admin/groups', body);
+    },
+    adminGetGroup(id) { return this._get(`/api/v1/admin/groups/${id}`); },
+    adminUpdateGroup(id, updates) { return this._put(`/api/v1/admin/groups/${id}`, updates); },
+    adminDeleteGroup(id) { return this._del(`/api/v1/admin/groups/${id}`); },
+    adminListGroupMembers(groupId) { return this._get(`/api/v1/admin/groups/${groupId}/members`); },
+    adminAddGroupMember(groupId, userId) { return this._post(`/api/v1/admin/groups/${groupId}/members`, { user_id: userId }); },
+    adminRemoveGroupMember(groupId, userId) { return this._del(`/api/v1/admin/groups/${groupId}/members/${userId}`); },
+
+    // ── Admin Resource Grants ───────────────
+    adminGetGrant(type, id) { return this._get(`/api/v1/admin/grants/${type}/${id}`); },
+    adminSetGrant(type, id, grantScope, grantedGroups) {
+        return this._put(`/api/v1/admin/grants/${type}/${id}`, { grant_scope: grantScope, granted_groups: grantedGroups || [] });
+    },
+    adminDeleteGrant(type, id) { return this._del(`/api/v1/admin/grants/${type}/${id}`); },
+
+    // ── User Groups ─────────────────────────
+    listMyGroups() { return this._get('/api/v1/groups/mine'); },
+
     // ── User Teams ──────────────────────────
     listMyTeams() { return this._get('/api/v1/teams/mine'); },
 
@@ -425,6 +449,7 @@ const API = {
     teamCreatePreset(teamId, preset) { return this._post(`/api/v1/teams/${teamId}/presets`, preset); },
     teamDeletePreset(teamId, presetId) { return this._del(`/api/v1/teams/${teamId}/presets/${presetId}`); },
     teamListAvailableModels(teamId) { return this._get(`/api/v1/teams/${teamId}/models`); },
+    teamListGroups(teamId) { return this._get(`/api/v1/teams/${teamId}/groups`); },
 
     // ── Team Providers ──────────────────────
     teamListProviders(teamId) { return this._get(`/api/v1/teams/${teamId}/providers`); },
diff --git a/src/js/knowledge-ui.js b/src/js/knowledge-ui.js
index 91ab467..10c406b 100644
--- a/src/js/knowledge-ui.js
+++ b/src/js/knowledge-ui.js
@@ -182,13 +182,14 @@ const KnowledgeUI = (() => {
                 const chunks = kb.chunk_count === 1 ? '1 chunk' : `${kb.chunk_count} chunks`;
                 const size = kb.total_bytes > 0 ? ` · ${_formatSize(kb.total_bytes)}` : '';
                 html += `
-                    <div class="kb-manage-item" data-kb-id="${kb.id}">
+                    <div class="kb-manage-item" data-kb-id="${kb.id}" data-grant-kb="${kb.id}">
                         <div class="kb-manage-info">
                             <span class="kb-manage-name">${scope} ${_esc(kb.name)}</span>
                             <span class="kb-manage-desc">${_esc(kb.description || '')}</span>
                             <span class="kb-manage-stats">${docs} · ${chunks}${size}${status}</span>
                         </div>
                         <div class="kb-manage-actions">
+                            ${kb.scope !== 'personal' ? `<button class="btn-small" data-kb-grant="${kb.id}" data-kb-name="${_esc(kb.name)}" title="Access">🔒</button>` : ''}
                             <button class="btn-small" data-kb-docs="${kb.id}" title="Documents">📄</button>
                             <button class="btn-small btn-danger" data-kb-del="${kb.id}" title="Delete">✕</button>
                         </div>
@@ -211,6 +212,14 @@ const KnowledgeUI = (() => {
         panel.querySelectorAll('[data-kb-del]').forEach(btn => {
             btn.addEventListener('click', () => _deleteKB(btn.dataset.kbDel));
         });
+        // Wire grant access buttons (admin only, non-personal KBs)
+        panel.querySelectorAll('[data-kb-grant]').forEach(btn => {
+            btn.addEventListener('click', () => {
+                if (typeof UI !== 'undefined' && UI.openGrantPicker) {
+                    UI.openGrantPicker('knowledge_base', btn.dataset.kbGrant, btn.dataset.kbName, `[data-grant-kb="${btn.dataset.kbGrant}"]`);
+                }
+            });
+        });
     }
 
     // ── Create KB Dialog ─────────────────────
diff --git a/src/js/ui-admin.js b/src/js/ui-admin.js
index 3f9e123..79b7584 100644
--- a/src/js/ui-admin.js
+++ b/src/js/ui-admin.js
@@ -6,14 +6,14 @@
 
 // ── Category → Section mapping ────────────
 const ADMIN_SECTIONS = {
-    people:     ['users', 'teams'],
+    people:     ['users', 'teams', 'groups'],
     ai:         ['providers', 'models', 'presets', 'roles', 'knowledgeBases'],
     system:     ['settings', 'storage', 'extensions'],
     monitoring: ['usage', 'audit', 'stats'],
 };
 
 const ADMIN_LABELS = {
-    users: 'Users', teams: 'Teams',
+    users: 'Users', teams: 'Teams', groups: 'Groups',
     providers: 'Providers', models: 'Models', presets: 'Personas', roles: 'Roles', knowledgeBases: 'Knowledge',
     settings: 'Settings', storage: 'Storage', extensions: 'Extensions',
     usage: 'Usage', audit: 'Audit', stats: 'Stats',
@@ -23,6 +23,7 @@ const ADMIN_LABELS = {
 const ADMIN_LOADERS = {
     users:      () => UI.loadAdminUsers(),
     teams:      () => UI.loadAdminTeams(),
+    groups:     () => UI.loadAdminGroups(),
     roles:      () => UI.loadAdminRoles(),
     providers:  () => UI.loadAdminProviders(),
     models:     () => UI.loadAdminModels(),
@@ -187,6 +188,7 @@ Object.assign(UI, {
                 KnowledgeUI.openTeamPanel(teamId);
             }
         }
+        if (tab === 'groups') UI.loadTeamManageGroups(teamId);
     },
 
     async loadAdminUsers(quiet) {
@@ -612,13 +614,14 @@ Object.assign(UI, {
                 }
                 const creator = p.creator_name ? `<span class="text-muted" style="font-size:11px">by ${esc(p.creator_name)}</span>` : '';
                 const status = p.is_active ? '' : '<span class="badge-pending">inactive</span>';
-                return `<div class="admin-preset-row">
+                return `<div class="admin-preset-row" data-grant-persona="${p.id}">
                     <div class="preset-info">
                         <strong>${avatarEl}${esc(p.name)}</strong> ${scopeBadge} ${creator} ${status}
                         <div class="preset-meta">${esc(p.base_model_id)} · ${esc(p.provider_name || 'auto')}</div>
                         ${p.description ? `<div class="preset-desc">${esc(p.description)}</div>` : ''}
                     </div>
                     <div class="preset-actions">
+                        <button class="btn-small" onclick="UI.openGrantPicker('persona', '${p.id}', '${esc(p.name)}', '[data-grant-persona=&quot;${p.id}&quot;]')" title="Manage access">🔒 Access</button>
                         <button class="btn-edit" onclick="editAdminPreset('${p.id}')" title="Edit">✎</button>
                         <button class="admin-model-toggle ${p.is_active ? 'enabled' : ''}" onclick="toggleAdminPreset('${p.id}', ${!p.is_active})">${p.is_active ? '✓ Active' : 'Inactive'}</button>
                         <button class="btn-delete" onclick="deleteAdminPreset('${p.id}', '${esc(p.name)}')" title="Delete">✕</button>
@@ -725,6 +728,146 @@ Object.assign(UI, {
         } catch (e) { sel.innerHTML = `<option value="">Error loading users</option>`; }
     },
 
+    // ── Groups Admin ────────────────────────
+    _groupEditId: null,
+
+    async loadAdminGroups(quiet) {
+        const el = document.getElementById('adminGroupList');
+        const detail = document.getElementById('adminGroupDetail');
+        if (!quiet) {
+            el.innerHTML = '<div class="loading">Loading...</div>';
+            detail.style.display = 'none';
+            el.style.display = '';
+            document.getElementById('adminAddGroupForm').style.display = 'none';
+        }
+        try {
+            const resp = await API.adminListGroups();
+            const groups = resp.data || [];
+            el.innerHTML = groups.map(g => {
+                const scopeBadge = g.scope === 'global'
+                    ? '<span class="badge-admin">global</span>'
+                    : `<span class="badge-team">team</span>`;
+                return `<div class="admin-user-row">
+                    <div class="admin-user-info">
+                        <div><strong>${esc(g.name)}</strong> ${scopeBadge}</div>
+                        <div class="text-muted">${esc(g.description || 'No description')} · ${g.member_count} member${g.member_count !== 1 ? 's' : ''}</div>
+                    </div>
+                    <div class="admin-user-actions">
+                        <button class="btn-small" onclick="UI.openGroupDetail('${g.id}', '${esc(g.name)}')">Members</button>
+                        <button class="btn-delete" onclick="deleteGroup('${g.id}', '${esc(g.name)}')" title="Delete">✕</button>
+                    </div>
+                </div>`;
+            }).join('') || '<div class="empty-hint">No groups yet — create one to control access to personas and knowledge bases</div>';
+        } catch (e) { el.innerHTML = `<div class="error-hint">${esc(e.message)}</div>`; }
+    },
+
+    async openGroupDetail(groupId, groupName) {
+        this._groupEditId = groupId;
+        document.getElementById('adminGroupList').style.display = 'none';
+        document.getElementById('adminAddGroupForm').style.display = 'none';
+        const detail = document.getElementById('adminGroupDetail');
+        detail.style.display = '';
+        document.getElementById('adminGroupDetailName').textContent = groupName;
+        document.getElementById('adminAddGroupMemberForm').style.display = 'none';
+
+        // Load group details for meta line
+        try {
+            const g = await API.adminGetGroup(groupId);
+            const scope = g.scope === 'global' ? 'Global group' : 'Team-scoped group';
+            document.getElementById('adminGroupDetailMeta').textContent = `${scope} · ${g.member_count} member${g.member_count !== 1 ? 's' : ''}`;
+        } catch (e) { /* proceed */ }
+
+        await this.loadGroupMembers(groupId);
+    },
+
+    async loadGroupMembers(groupId) {
+        const el = document.getElementById('adminGroupMemberList');
+        el.innerHTML = '<div class="loading">Loading...</div>';
+        try {
+            const resp = await API.adminListGroupMembers(groupId);
+            const members = resp.data || [];
+            el.innerHTML = members.map(m => `
+                <div class="admin-user-row">
+                    <div class="admin-user-info">
+                        <div><strong>${esc(m.display_name || m.username || m.email)}</strong></div>
+                        <div class="text-muted">${esc(m.email)} · added ${new Date(m.added_at).toLocaleDateString()}</div>
+                    </div>
+                    <div class="admin-user-actions">
+                        <button class="btn-delete" onclick="removeGroupMember('${groupId}', '${m.user_id}', '${esc(m.username || m.email)}')" title="Remove">✕</button>
+                    </div>
+                </div>
+            `).join('') || '<div class="empty-hint">No members — add users to this group</div>';
+        } catch (e) { el.innerHTML = `<div class="error-hint">${esc(e.message)}</div>`; }
+    },
+
+    async loadGroupMemberDropdown(groupId) {
+        const sel = document.getElementById('adminGroupMemberUser');
+        sel.innerHTML = '<option value="">Loading...</option>';
+        try {
+            const resp = await API.adminListUsers(1, 200);
+            const users = resp.users || resp.data || [];
+            // Exclude existing members
+            const memberResp = await API.adminListGroupMembers(groupId);
+            const existingIds = new Set((memberResp.data || []).map(m => m.user_id));
+            const available = users.filter(u => u.is_active && !existingIds.has(u.id));
+            sel.innerHTML = '<option value="">Select user...</option>' +
+                available.map(u => `<option value="${u.id}">${esc(u.username || u.email)}</option>`).join('');
+        } catch (e) { sel.innerHTML = `<option value="">Error loading users</option>`; }
+    },
+
+    // ── Grant Picker (shared for Personas + KBs) ──
+
+    async openGrantPicker(resourceType, resourceId, resourceName, anchorSelector) {
+        // Fetch current grant + all groups for the picker
+        const [grantResp, groupsResp] = await Promise.all([
+            API.adminGetGrant(resourceType, resourceId),
+            API.adminListGroups(),
+        ]);
+        const grant = grantResp;
+        const groups = (groupsResp.data || []);
+        const currentScope = grant.grant_scope || 'team_only';
+        const currentGroups = new Set(grant.granted_groups || []);
+
+        const html = `<div class="admin-inline-form" style="margin:8px 0;padding:10px;background:rgba(255,255,255,0.03);border-radius:8px">
+            <div style="font-size:13px;font-weight:600;margin-bottom:8px">Access: ${esc(resourceName)}</div>
+            <div class="form-group" style="margin-bottom:8px">
+                <label style="font-size:12px">Scope</label>
+                <select id="grantScope_${resourceId}" class="inline-select" style="width:auto">
+                    <option value="team_only" ${currentScope === 'team_only' ? 'selected' : ''}>Team Only (default)</option>
+                    <option value="global" ${currentScope === 'global' ? 'selected' : ''}>Global (all users)</option>
+                    <option value="groups" ${currentScope === 'groups' ? 'selected' : ''}>Specific Groups</option>
+                </select>
+            </div>
+            <div id="grantGroups_${resourceId}" style="${currentScope === 'groups' ? '' : 'display:none'}">
+                ${groups.length ? groups.map(g => `<label class="checkbox-label" style="font-size:12px">
+                    <input type="checkbox" class="grant-group-cb" value="${g.id}" ${currentGroups.has(g.id) ? 'checked' : ''}> ${esc(g.name)}
+                    <span class="text-muted" style="font-size:11px">${g.scope === 'global' ? '(global)' : '(team)'}</span>
+                </label>`).join('') : '<span class="text-muted" style="font-size:12px">No groups exist yet — create one in People → Groups</span>'}
+            </div>
+            <div class="form-row" style="margin-top:8px">
+                <button class="btn-small btn-primary" onclick="saveGrant('${resourceType}', '${resourceId}')">Save</button>
+                <button class="btn-small" onclick="this.closest('.admin-inline-form').remove()">Cancel</button>
+            </div>
+        </div>`;
+
+        // Remove any existing picker, then insert after the anchor row
+        document.querySelectorAll('.grant-picker-active').forEach(el => el.remove());
+        const row = document.querySelector(anchorSelector);
+        if (row) {
+            const wrapper = document.createElement('div');
+            wrapper.className = 'grant-picker-active';
+            wrapper.innerHTML = html;
+            row.after(wrapper);
+
+            // Wire scope toggle
+            const scopeSel = document.getElementById(`grantScope_${resourceId}`);
+            const groupsDiv = document.getElementById(`grantGroups_${resourceId}`);
+            scopeSel?.addEventListener('change', () => {
+                groupsDiv.style.display = scopeSel.value === 'groups' ? '' : 'none';
+            });
+        }
+    },
+
     async loadAdminSettings() {
         try {
             const data = await API.adminGetSettings();
diff --git a/src/js/ui-settings.js b/src/js/ui-settings.js
index a6ac421..b4e3b76 100644
--- a/src/js/ui-settings.js
+++ b/src/js/ui-settings.js
@@ -301,6 +301,24 @@ Object.assign(UI, {
         } catch (e) { el.innerHTML = `<div class="error-hint">${esc(e.message)}</div>`; }
     },
 
+    async loadTeamManageGroups(teamId) {
+        const el = document.getElementById('settingsTeamGroups');
+        if (!el) return;
+        el.innerHTML = '<div class="loading">Loading...</div>';
+        try {
+            const resp = await API.teamListGroups(teamId);
+            const groups = resp.data || [];
+            el.innerHTML = groups.map(g => `
+                <div class="admin-user-row" style="padding:6px 0">
+                    <div class="admin-user-info">
+                        <div><strong>${esc(g.name)}</strong></div>
+                        <div class="text-muted" style="font-size:11px">${esc(g.description || 'No description')} · ${g.member_count} member${g.member_count !== 1 ? 's' : ''}</div>
+                    </div>
+                </div>
+            `).join('') || '<div class="empty-hint">No groups assigned to this team yet</div>';
+        } catch (e) { el.innerHTML = `<div class="error-hint">${esc(e.message)}</div>`; }
+    },
+
     async loadMyUsage() {
         const el = document.getElementById('myUsageTotals')?.parentElement;
         if (!el) return;