diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7e1afa2..f57651e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,41 @@
 
 All notable changes to Armature are documented here.
 
+## v0.6.15 — User Display Audit
+
+Every user-facing identity surface now shows human-readable names instead of
+UUIDs, with the canonical fallback chain: `display_name → username → "Unknown"`.
+
+### Added
+
+- **`GET /api/v1/users/resolve?ids=...`** — batch endpoint returns identity
+  records (username, display_name, handle, avatar_url) for up to 100 user IDs.
+  Response keyed by ID for O(1) client lookups.
+- **`sw.users` SDK module** — `resolve(id)`, `resolveMany(ids)`,
+  `displayName(user)` with 60-second local cache. Surfaces use this instead
+  of ad-hoc lookups or stale snapshots.
+- **5 handler tests** for the resolve endpoint (single, multiple, missing,
+  empty, no-param).
+
+### Changed
+
+- **Admin users list** — shows `display_name || username` as primary
+  identifier, with username shown as secondary when display_name is set.
+- **Admin teams/groups member lists** — replaced `username || user_id`
+  with `display_name || username || 'Unknown'`.
+- **Team-admin members** — dropdown and list now show display_name.
+- **Chat participants** — resolved from users table via `sw.users.resolveMany()`
+  instead of relying on creation-time snapshot. Message sender names, typing
+  indicators, and participant sidebar all use resolved names.
+- **Dashboard greeting** — added `|| 'Unknown'` terminal fallback.
+- **Team activity log** — capitalized fallback to `'Unknown'`.
+
+### Deprecated
+
+- **`participants.display_name` column** in chat-core — column retained for
+  backward compatibility but UI no longer relies on snapshot values. Comments
+  added to `packages/chat-core/script.star` noting deprecation.
+
 ## v0.6.14 — Visual Polish
 
 Systematic cleanup of stale values, self-hosted fonts, and rendering fixes.
diff --git a/ROADMAP-UI.md b/ROADMAP-UI.md
index 461f206..d85e336 100644
--- a/ROADMAP-UI.md
+++ b/ROADMAP-UI.md
@@ -91,17 +91,13 @@ Shipped. Stale fallback colors purged (~65 instances), fonts self-hosted
 regressions (half-step tokens), theme settings default, surface overflow,
 and user menu zoom drift. See CHANGELOG.md.
 
-### v0.6.15 — User Display Audit
+### v0.6.15 — User Display Audit ✅
 
-Every place a user identity appears in the UI must show a human-readable
-name, never a UUID. Fallback chain: `display_name → username → "Unknown"`.
-
-| Step | Description |
-|------|-------------|
-| Participant display-name resolution | `chat-core` participants endpoint resolves `display_name` from the users table at query time instead of relying on a creation-time snapshot. If the stored `display_name` is empty, look up `users.display_name` or `users.username` by `participant_id`. |
-| Audit all user-facing identity surfaces | Walk every surface that shows user identity: chat participant list, chat message sender names, chat typing indicators, workflow assignees, team member lists, admin user list, notification actor names. Ensure the fallback chain is `display_name → username → "Unknown"` everywhere. |
-| SDK user-resolve utility | Add `sw.users.resolve(id)` or similar to the SDK — returns `{id, username, display_name, avatar}` with local caching. Surfaces use this instead of ad-hoc lookups. |
-| Stale snapshot cleanup | Remove or deprecate the static `display_name` column in the participants table. All display names come from the users table via the resolve utility. |
+Shipped. `GET /api/v1/users/resolve?ids=...` batch endpoint, `sw.users`
+SDK module with `resolve()`, `resolveMany()`, `displayName()` + 60s cache.
+Chat participants resolved from users table instead of snapshot. All admin
+surfaces show `display_name || username || 'Unknown'`. Chat-core snapshot
+column deprecated. 5 new handler tests. See CHANGELOG.md.
 
 ### v0.6.16 — Usability Survey Gate
 
@@ -133,7 +129,7 @@ v0.6.13 Responsive & Spacing    ✅ SHIPPED
   ↓
 v0.6.14 Visual Polish           ✅ SHIPPED
   ↓
-v0.6.15 User Display Audit     ← No UUIDs in the UI, ever
+v0.6.15 User Display Audit     ✅ SHIPPED
   ↓
 v0.6.16 Usability Survey Gate   ← Machine-audit the finished product
 ```
diff --git a/VERSION b/VERSION
index fcbaa84..6769f67 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-0.6.14
+0.6.15
diff --git a/packages/chat-core/script.star b/packages/chat-core/script.star
index a41fa38..0187836 100644
--- a/packages/chat-core/script.star
+++ b/packages/chat-core/script.star
@@ -91,6 +91,9 @@ def create(title, type="group", participants=None, creator_id="", creator_displa
     cid = conv["id"]
 
     # Add creator as admin participant
+    # NOTE: display_name is a snapshot captured at creation time.
+    # DEPRECATED v0.6.15 — UI resolves display names from users table via sw.users.resolve().
+    # Column retained for backward compatibility; UI no longer relies on this value for display.
     if creator_id:
         db.insert("participants", {
             "conversation_id": cid,
@@ -110,7 +113,7 @@ def create(title, type="group", participants=None, creator_id="", creator_displa
             "conversation_id": cid,
             "participant_id": pid,
             "participant_type": _str(p.get("type", "user")),
-            "display_name": _str(p.get("display_name", "")),
+            "display_name": _str(p.get("display_name", "")),  # DEPRECATED v0.6.15 — snapshot only
             "role": _str(p.get("role", "member")),
             "joined_at": "",
         })
@@ -213,7 +216,7 @@ def add_participant(conversation_id, participant_id, participant_type="user", di
         "conversation_id": cid,
         "participant_id": pid,
         "participant_type": _str(participant_type),
-        "display_name": _str(display_name),
+        "display_name": _str(display_name),  # DEPRECATED v0.6.15 — snapshot only
         "role": _str(role),
         "joined_at": "",
     })
diff --git a/packages/chat/js/main.js b/packages/chat/js/main.js
index 1b33689..83c86a1 100644
--- a/packages/chat/js/main.js
+++ b/packages/chat/js/main.js
@@ -243,9 +243,9 @@
            onMouseEnter=${() => setHover(true)}
            onMouseLeave=${() => setHover(false)}>
         ${!isOwn && html`
-          <${Avatar} name=${msg._display_name || msg.participant_id} size="sm" />`}
+          <${Avatar} name=${msg._display_name || 'Unknown'} size="sm" />`}
         <div class="ext-chat-msg__body">
-          ${!isOwn && html`<span class="ext-chat-msg__name">${msg._display_name || msg.participant_id}</span>`}
+          ${!isOwn && html`<span class="ext-chat-msg__name">${msg._display_name || 'Unknown'}</span>`}
           ${editing ? html`
             <div class="ext-chat-msg__edit">
               <textarea class="ext-chat-msg__edit-input"
@@ -285,20 +285,32 @@
     var [hasMore, setHasMore] = useState(false);
     var [nextCursor, setNextCursor] = useState('');
     var [typingUsers, setTypingUsers] = useState({});
+    var [resolvedNames, setResolvedNames] = useState({});
     var bottomRef = useRef(null);
     var listRef = useRef(null);
     var userId = currentUserId();
 
-    // Build participant lookup
+    // Resolve participant display names from users table (not snapshot)
+    useEffect(() => {
+      var ids = (participants || []).map(p => p.participant_id).filter(Boolean);
+      if (ids.length === 0) return;
+      sw.users.resolveMany(ids).then(map => {
+        var names = {};
+        map.forEach((user, id) => { names[id] = sw.users.displayName(user); });
+        setResolvedNames(names);
+      });
+    }, [participants]);
+
+    // Build participant lookup from resolved names
     var partMap = useMemo(() => {
       var m = {};
-      (participants || []).forEach(p => { m[p.participant_id] = p.display_name || p.participant_id; });
+      (participants || []).forEach(p => { m[p.participant_id] = resolvedNames[p.participant_id] || p.display_name || 'Unknown'; });
       return m;
-    }, [participants]);
+    }, [participants, resolvedNames]);
 
     // Enrich messages with display names
     function enrichMessages(msgs) {
-      return msgs.map(m => ({ ...m, _display_name: partMap[m.participant_id] || m.participant_id }));
+      return msgs.map(m => ({ ...m, _display_name: partMap[m.participant_id] || 'Unknown' }));
     }
 
     // Load initial messages
@@ -361,7 +373,7 @@
 
       var unsubs = [
         sw.realtime.subscribe(channel, 'message', (payload) => {
-          var msg = { ...payload, _display_name: partMap[payload.participant_id] || payload.participant_id };
+          var msg = { ...payload, _display_name: partMap[payload.participant_id] || 'Unknown' };
           setMessages(prev => [...prev, msg]);
           setTimeout(() => scrollToBottom(), 50);
           // Auto mark read if from someone else
@@ -386,7 +398,8 @@
       unsubs.push(sw.realtime.subscribe(channel, 'typing', (payload) => {
         var pid = payload.participant_id;
         if (pid === userId) return;
-        setTypingUsers(prev => ({ ...prev, [pid]: payload.display_name || pid }));
+        var typingName = resolvedNames[pid] || payload.display_name || 'Someone';
+        setTypingUsers(prev => ({ ...prev, [pid]: typingName }));
         clearTimeout(typingTimers[pid]);
         typingTimers[pid] = setTimeout(() => {
           setTypingUsers(prev => {
@@ -553,6 +566,18 @@
   function ParticipantSidebar({ conversationId, participants, onRefresh, isAdmin }) {
     var [addOpen, setAddOpen] = useState(false);
     var [presence, setPresence] = useState({});
+    var [resolvedNames, setResolvedNames] = useState({});
+
+    // Resolve display names from users table
+    useEffect(() => {
+      var ids = (participants || []).map(p => p.participant_id).filter(Boolean);
+      if (ids.length === 0) return;
+      sw.users.resolveMany(ids).then(map => {
+        var names = {};
+        map.forEach((user, id) => { names[id] = sw.users.displayName(user); });
+        setResolvedNames(names);
+      });
+    }, [participants]);
 
     // Query presence
     useEffect(() => {
@@ -588,9 +613,9 @@
         <div class="ext-chat-participants__list">
           ${(participants || []).map(p => html`
             <div key=${p.participant_id} class="ext-chat-participants__item">
-              <${Avatar} name=${p.display_name || p.participant_id} size="sm" />
+              <${Avatar} name=${resolvedNames[p.participant_id] || p.display_name || 'Unknown'} size="sm" />
               <span class="ext-chat-participants__name">
-                ${p.display_name || p.participant_id}
+                ${resolvedNames[p.participant_id] || p.display_name || 'Unknown'}
                 ${p.role === 'admin' && html`<span class="ext-chat-participants__badge">admin</span>`}
               </span>
               <span class=${'chat-participants__status' + (presence[p.participant_id] ? ' ext-chat-participants__status--online' : '')} />
diff --git a/packages/dashboard/js/main.js b/packages/dashboard/js/main.js
index d243760..29d9681 100644
--- a/packages/dashboard/js/main.js
+++ b/packages/dashboard/js/main.js
@@ -156,7 +156,7 @@
         const user = sw.user;
         const greeting = document.createElement('div');
         greeting.className = 'ext-dashboard-greeting';
-        greeting.textContent = 'Welcome back' + (user ? ', ' + (user.display_name || user.username) : '');
+        greeting.textContent = 'Welcome back' + (user ? ', ' + (user.display_name || user.username || 'Unknown') : '');
         main.appendChild(greeting);
 
         const subtitle = document.createElement('div');
diff --git a/packages/team-activity-log/js/main.js b/packages/team-activity-log/js/main.js
index 814477d..b0e86c8 100644
--- a/packages/team-activity-log/js/main.js
+++ b/packages/team-activity-log/js/main.js
@@ -181,7 +181,7 @@
           <div key=${e.id} class="ext-team-activity-log-entry">
             <div class="ext-team-activity-log-entry__header">
               <span class="ext-team-activity-log-entry__category badge">${e.category}</span>
-              <span class="ext-team-activity-log-entry__user">${esc(e.username || 'unknown')}</span>
+              <span class="ext-team-activity-log-entry__user">${esc(e.username || 'Unknown')}</span>
               <span class="ext-team-activity-log-entry__time">${timeAgo(e.created_at)}</span>
               <button class="ext-team-activity-log-entry__delete" onClick=${() => onDelete(e.id)}
                       title="Delete">×</button>
diff --git a/server/handlers/presence.go b/server/handlers/presence.go
index edb3979..d7b4dc5 100644
--- a/server/handlers/presence.go
+++ b/server/handlers/presence.go
@@ -81,3 +81,38 @@ func (h *PresenceHandler) SearchUsers(c *gin.Context) {
 	}
 	c.JSON(http.StatusOK, gin.H{"data": results})
 }
+
+// ResolveUsers returns identity records for a batch of user IDs.
+// GET /api/v1/users/resolve?ids=uuid1,uuid2,...
+func (h *PresenceHandler) ResolveUsers(c *gin.Context) {
+	raw := strings.TrimSpace(c.Query("ids"))
+	if raw == "" {
+		c.JSON(http.StatusOK, gin.H{"data": map[string]interface{}{}})
+		return
+	}
+
+	ids := make([]string, 0)
+	for _, id := range strings.Split(raw, ",") {
+		id = strings.TrimSpace(id)
+		if id != "" {
+			ids = append(ids, id)
+		}
+	}
+	if len(ids) == 0 {
+		c.JSON(http.StatusOK, gin.H{"data": map[string]interface{}{}})
+		return
+	}
+
+	results, err := h.stores.Users.ResolveByIDs(c.Request.Context(), ids)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "resolve failed"})
+		return
+	}
+
+	// Build map keyed by user ID for O(1) client-side lookups
+	m := make(map[string]interface{}, len(results))
+	for _, u := range results {
+		m[u.ID] = u
+	}
+	c.JSON(http.StatusOK, gin.H{"data": m})
+}
diff --git a/server/handlers/presence_test.go b/server/handlers/presence_test.go
new file mode 100644
index 0000000..df4e212
--- /dev/null
+++ b/server/handlers/presence_test.go
@@ -0,0 +1,179 @@
+package handlers
+
+import (
+	"encoding/json"
+	"net/http"
+	"testing"
+
+	"github.com/gin-gonic/gin"
+
+	"armature/config"
+	"armature/database"
+	"armature/middleware"
+	"armature/store"
+	postgres "armature/store/postgres"
+	sqlite "armature/store/sqlite"
+)
+
+// ── Presence/Resolve Test Harness ──────────────
+
+type presenceHarness struct {
+	*testHarness
+	stores    store.Stores
+	userToken string
+	userID    string
+}
+
+func setupPresenceHarness(t *testing.T) *presenceHarness {
+	t.Helper()
+	database.RequireTestDB(t)
+	database.TruncateAll(t)
+
+	cfg := &config.Config{
+		JWTSecret: testJWTSecret,
+		BasePath:  "",
+	}
+
+	var stores store.Stores
+	if database.IsSQLite() {
+		stores = sqlite.NewStores(database.TestDB)
+	} else {
+		stores = postgres.NewStores(database.TestDB)
+	}
+	userCache := middleware.NewUserStatusCache()
+
+	r := gin.New()
+	api := r.Group("/api/v1")
+	protected := api.Group("")
+	protected.Use(middleware.Auth(cfg, stores.Users, userCache))
+
+	presence := NewPresenceHandler(stores)
+	protected.GET("/users/resolve", presence.ResolveUsers)
+	protected.GET("/users/search", presence.SearchUsers)
+
+	// Seed a caller user
+	userID := database.SeedTestUser(t, "caller", "caller@test.com")
+	database.TestDB.Exec(dialectSQL("UPDATE users SET is_active = true WHERE id = $1"), userID)
+	userToken := makeToken(userID, "caller@test.com", "user")
+
+	return &presenceHarness{
+		testHarness: &testHarness{router: r, t: t},
+		stores:      stores,
+		userToken:   userToken,
+		userID:      userID,
+	}
+}
+
+// ── Tests ──────────────────────────────────────
+
+func TestResolveUsers_SingleID(t *testing.T) {
+	h := setupPresenceHarness(t)
+
+	// Seed a user with display_name
+	targetID := database.SeedTestUser(t, "alice", "alice@test.com")
+	database.TestDB.Exec(dialectSQL("UPDATE users SET is_active = true, display_name = $1 WHERE id = $2"), "Alice Smith", targetID)
+
+	w := h.request("GET", "/api/v1/users/resolve?ids="+targetID, h.userToken, nil)
+	if w.Code != http.StatusOK {
+		t.Fatalf("expected 200, got %d: %s", w.Code, w.Body.String())
+	}
+
+	var resp struct {
+		Data map[string]store.UserSearchResult `json:"data"`
+	}
+	json.NewDecoder(w.Body).Decode(&resp)
+
+	u, ok := resp.Data[targetID]
+	if !ok {
+		t.Fatalf("expected user %s in response, got %v", targetID, resp.Data)
+	}
+	if u.Username != "alice" {
+		t.Errorf("expected username 'alice', got %q", u.Username)
+	}
+	if u.DisplayName != "Alice Smith" {
+		t.Errorf("expected display_name 'Alice Smith', got %q", u.DisplayName)
+	}
+}
+
+func TestResolveUsers_MultipleIDs(t *testing.T) {
+	h := setupPresenceHarness(t)
+
+	id1 := database.SeedTestUser(t, "bob", "bob@test.com")
+	id2 := database.SeedTestUser(t, "carol", "carol@test.com")
+	database.TestDB.Exec(dialectSQL("UPDATE users SET is_active = true WHERE id = $1"), id1)
+	database.TestDB.Exec(dialectSQL("UPDATE users SET is_active = true, display_name = $1 WHERE id = $2"), "Carol D", id2)
+
+	w := h.request("GET", "/api/v1/users/resolve?ids="+id1+","+id2, h.userToken, nil)
+	if w.Code != http.StatusOK {
+		t.Fatalf("expected 200, got %d", w.Code)
+	}
+
+	var resp struct {
+		Data map[string]store.UserSearchResult `json:"data"`
+	}
+	json.NewDecoder(w.Body).Decode(&resp)
+
+	if len(resp.Data) != 2 {
+		t.Fatalf("expected 2 users, got %d", len(resp.Data))
+	}
+	if resp.Data[id1].Username != "bob" {
+		t.Errorf("expected bob, got %q", resp.Data[id1].Username)
+	}
+	if resp.Data[id2].DisplayName != "Carol D" {
+		t.Errorf("expected 'Carol D', got %q", resp.Data[id2].DisplayName)
+	}
+}
+
+func TestResolveUsers_MissingID(t *testing.T) {
+	h := setupPresenceHarness(t)
+
+	w := h.request("GET", "/api/v1/users/resolve?ids=00000000-0000-0000-0000-000000000099", h.userToken, nil)
+	if w.Code != http.StatusOK {
+		t.Fatalf("expected 200, got %d", w.Code)
+	}
+
+	var resp struct {
+		Data map[string]store.UserSearchResult `json:"data"`
+	}
+	json.NewDecoder(w.Body).Decode(&resp)
+
+	if len(resp.Data) != 0 {
+		t.Errorf("expected empty map for missing ID, got %d entries", len(resp.Data))
+	}
+}
+
+func TestResolveUsers_EmptyParam(t *testing.T) {
+	h := setupPresenceHarness(t)
+
+	w := h.request("GET", "/api/v1/users/resolve?ids=", h.userToken, nil)
+	if w.Code != http.StatusOK {
+		t.Fatalf("expected 200, got %d", w.Code)
+	}
+
+	var resp struct {
+		Data map[string]interface{} `json:"data"`
+	}
+	json.NewDecoder(w.Body).Decode(&resp)
+
+	if len(resp.Data) != 0 {
+		t.Errorf("expected empty map, got %d entries", len(resp.Data))
+	}
+}
+
+func TestResolveUsers_NoParam(t *testing.T) {
+	h := setupPresenceHarness(t)
+
+	w := h.request("GET", "/api/v1/users/resolve", h.userToken, nil)
+	if w.Code != http.StatusOK {
+		t.Fatalf("expected 200, got %d", w.Code)
+	}
+
+	var resp struct {
+		Data map[string]interface{} `json:"data"`
+	}
+	json.NewDecoder(w.Body).Decode(&resp)
+
+	if len(resp.Data) != 0 {
+		t.Errorf("expected empty map, got %d entries", len(resp.Data))
+	}
+}
diff --git a/server/main.go b/server/main.go
index 212b628..9fc7e25 100644
--- a/server/main.go
+++ b/server/main.go
@@ -474,8 +474,9 @@ func main() {
 			protected.POST("/presence/heartbeat", presence.Heartbeat)
 			protected.GET("/presence", presence.Query)
 
-			// User search
+			// User search & resolve
 			protected.GET("/users/search", presence.SearchUsers)
+			protected.GET("/users/resolve", presence.ResolveUsers)
 
 			// Workflows
 			wfH := handlers.NewWorkflowHandler(stores)
diff --git a/server/static/openapi.yaml b/server/static/openapi.yaml
index 730496f..932ce3d 100644
--- a/server/static/openapi.yaml
+++ b/server/static/openapi.yaml
@@ -1355,6 +1355,42 @@ paths:
                     items:
                       type: object
 
+  /api/v1/users/resolve:
+    get:
+      summary: Resolve user identities by ID
+      operationId: resolveUsers
+      tags: [Presence]
+      parameters:
+        - name: ids
+          in: query
+          required: true
+          description: Comma-separated user IDs (max 100)
+          schema:
+            type: string
+      responses:
+        '200':
+          description: Map of user ID to identity record
+          content:
+            application/json:
+              schema:
+                type: object
+                properties:
+                  data:
+                    type: object
+                    additionalProperties:
+                      type: object
+                      properties:
+                        id:
+                          type: string
+                        username:
+                          type: string
+                        display_name:
+                          type: string
+                        handle:
+                          type: string
+                        avatar_url:
+                          type: string
+
   # ──────────────────────────────────────────────
   # Notifications
   # ──────────────────────────────────────────────
diff --git a/server/store/interfaces.go b/server/store/interfaces.go
index 9640a1f..39368d6 100644
--- a/server/store/interfaces.go
+++ b/server/store/interfaces.go
@@ -103,6 +103,10 @@ type UserStore interface {
 	// Excludes the calling user. Max 20 results.
 	SearchActive(ctx context.Context, excludeUserID, query string) ([]UserSearchResult, error)
 
+	// ResolveByIDs returns lightweight identity records for the given user IDs.
+	// Missing IDs are silently omitted. Max 100 IDs.
+	ResolveByIDs(ctx context.Context, ids []string) ([]UserSearchResult, error)
+
 	// ── CS2 additions ──
 
 	// CountAll returns the total number of users.
@@ -132,6 +136,7 @@ type UserSearchResult struct {
 	Username    string `json:"username"`
 	DisplayName string `json:"display_name"`
 	Handle      string `json:"handle"`
+	AvatarURL   string `json:"avatar_url,omitempty"`
 }
 
 // =========================================
diff --git a/server/store/postgres/user.go b/server/store/postgres/user.go
index bb6238b..6f8fd45 100644
--- a/server/store/postgres/user.go
+++ b/server/store/postgres/user.go
@@ -250,6 +250,47 @@ func (s *UserStore) SearchActive(ctx context.Context, excludeUserID, query strin
 	return results, rows.Err()
 }
 
+// ResolveByIDs returns lightweight identity records for the given user IDs.
+func (s *UserStore) ResolveByIDs(ctx context.Context, ids []string) ([]store.UserSearchResult, error) {
+	if len(ids) == 0 {
+		return []store.UserSearchResult{}, nil
+	}
+	if len(ids) > 100 {
+		ids = ids[:100]
+	}
+
+	// Build $1,$2,... placeholders
+	placeholders := make([]string, len(ids))
+	args := make([]interface{}, len(ids))
+	for i, id := range ids {
+		placeholders[i] = fmt.Sprintf("$%d", i+1)
+		args[i] = id
+	}
+
+	q := `SELECT id, username, COALESCE(display_name, '') AS display_name,
+	             COALESCE(handle, '') AS handle, COALESCE(avatar_url, '') AS avatar_url
+	      FROM users WHERE id IN (` + strings.Join(placeholders, ",") + `)`
+
+	rows, err := DB.QueryContext(ctx, q, args...)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	var results []store.UserSearchResult
+	for rows.Next() {
+		var u store.UserSearchResult
+		if err := rows.Scan(&u.ID, &u.Username, &u.DisplayName, &u.Handle, &u.AvatarURL); err != nil {
+			continue
+		}
+		results = append(results, u)
+	}
+	if results == nil {
+		results = []store.UserSearchResult{}
+	}
+	return results, rows.Err()
+}
+
 // ── CS2 additions ─────────────────────────────────────────────
 
 func (s *UserStore) MergeSettings(ctx context.Context, userID string, patch []byte) error {
diff --git a/server/store/sqlite/user.go b/server/store/sqlite/user.go
index 8304372..43cc7ff 100644
--- a/server/store/sqlite/user.go
+++ b/server/store/sqlite/user.go
@@ -262,6 +262,47 @@ func (s *UserStore) SearchActive(ctx context.Context, excludeUserID, query strin
 	return results, rows.Err()
 }
 
+// ResolveByIDs returns lightweight identity records for the given user IDs.
+func (s *UserStore) ResolveByIDs(ctx context.Context, ids []string) ([]store.UserSearchResult, error) {
+	if len(ids) == 0 {
+		return []store.UserSearchResult{}, nil
+	}
+	if len(ids) > 100 {
+		ids = ids[:100]
+	}
+
+	// Build ?,?,... placeholders
+	placeholders := make([]string, len(ids))
+	args := make([]interface{}, len(ids))
+	for i, id := range ids {
+		placeholders[i] = "?"
+		args[i] = id
+	}
+
+	q := `SELECT id, username, COALESCE(display_name, '') AS display_name,
+	             COALESCE(handle, '') AS handle, COALESCE(avatar_url, '') AS avatar_url
+	      FROM users WHERE id IN (` + strings.Join(placeholders, ",") + `)`
+
+	rows, err := DB.QueryContext(ctx, q, args...)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	var results []store.UserSearchResult
+	for rows.Next() {
+		var u store.UserSearchResult
+		if err := rows.Scan(&u.ID, &u.Username, &u.DisplayName, &u.Handle, &u.AvatarURL); err != nil {
+			continue
+		}
+		results = append(results, u)
+	}
+	if results == nil {
+		results = []store.UserSearchResult{}
+	}
+	return results, rows.Err()
+}
+
 // ── CS2 additions ─────────────────────────────────────────────
 
 func (s *UserStore) MergeSettings(ctx context.Context, userID string, patch []byte) error {
diff --git a/src/js/sw/sdk/api-domains.js b/src/js/sw/sdk/api-domains.js
index 0264a5b..18b7f70 100644
--- a/src/js/sw/sdk/api-domains.js
+++ b/src/js/sw/sdk/api-domains.js
@@ -287,7 +287,8 @@ export function createDomains(restClient) {
 
         // ── Users ──────────────────────────────
         users: {
-            search: (q) => rc.get('/api/v1/users/search' + _qs({ q })),
+            search:  (q)   => rc.get('/api/v1/users/search' + _qs({ q })),
+            resolve: (ids) => rc.get('/api/v1/users/resolve' + _qs({ ids: ids.join(',') })),
         },
 
         presence: {
diff --git a/src/js/sw/sdk/index.js b/src/js/sw/sdk/index.js
index 7271b03..0ebefa5 100644
--- a/src/js/sw/sdk/index.js
+++ b/src/js/sw/sdk/index.js
@@ -24,6 +24,7 @@ import { createActions }    from './actions.js';
 import { createRealtime }   from './realtime.js';
 import { createRenderers }  from './renderers.js';
 import { createMarkdown }   from './markdown.js';
+import { createUsers }      from './users.js';
 import { confirm }          from '../primitives/confirm.js';
 import { prompt }           from '../primitives/prompt.js';
 
@@ -117,6 +118,9 @@ export async function boot() {
     // Markdown — unified renderer (marked + DOMPurify + sw.renderers pipeline)
     sw.markdown = markdown;
 
+    // Users — identity resolution with local caching
+    sw.users = createUsers(restClient);
+
     // Shell helpers — imperative confirm/prompt backed by primitives
     sw.confirm = confirm;
     sw.prompt  = prompt;
diff --git a/src/js/sw/sdk/users.js b/src/js/sw/sdk/users.js
new file mode 100644
index 0000000..83afd6b
--- /dev/null
+++ b/src/js/sw/sdk/users.js
@@ -0,0 +1,104 @@
+// ==========================================
+// Armature — SDK Users Module
+// ==========================================
+// Resolves user identity by ID with local caching.
+//
+// Usage:
+//   const user = await sw.users.resolve(id);
+//   const name = sw.users.displayName(user);
+//   const map  = await sw.users.resolveMany([id1, id2]);
+//
+// Cache: 60-second TTL per entry. Batch-fetches missing
+// IDs in a single GET /api/v1/users/resolve?ids=... call.
+// ==========================================
+
+const CACHE_TTL = 60_000; // 60 seconds
+
+/**
+ * @param {object} restClient — SDK rest client (rc.get, rc.post, etc.)
+ * @returns {object} sw.users namespace
+ */
+export function createUsers(restClient) {
+    /** @type {Map<string, {data: object, fetchedAt: number}>} */
+    const _cache = new Map();
+
+    function _isFresh(entry) {
+        return entry && (Date.now() - entry.fetchedAt) < CACHE_TTL;
+    }
+
+    /**
+     * Resolve multiple user IDs to identity records.
+     * Deduplicates, checks cache, fetches remainder in one API call.
+     *
+     * @param {string[]} ids
+     * @returns {Promise<Map<string, {id, username, display_name, avatar_url}>>}
+     */
+    async function resolveMany(ids) {
+        const unique = [...new Set(ids)].filter(Boolean);
+        const result = new Map();
+        const toFetch = [];
+
+        for (const id of unique) {
+            const cached = _cache.get(id);
+            if (_isFresh(cached)) {
+                result.set(id, cached.data);
+            } else {
+                toFetch.push(id);
+            }
+        }
+
+        if (toFetch.length > 0) {
+            try {
+                const resp = await restClient.get(
+                    '/api/v1/users/resolve?ids=' + encodeURIComponent(toFetch.join(','))
+                );
+                // REST client does NOT auto-unwrap {data: Object} (only arrays).
+                const data = (resp && resp.data) || resp || {};
+                for (const id of toFetch) {
+                    const user = data[id] || { id, username: '', display_name: '', avatar_url: '' };
+                    _cache.set(id, { data: user, fetchedAt: Date.now() });
+                    result.set(id, user);
+                }
+            } catch (err) {
+                console.warn('[sw.users] resolve failed:', err.message);
+                // Return empty placeholders for unfetched IDs
+                for (const id of toFetch) {
+                    const placeholder = { id, username: '', display_name: '', avatar_url: '' };
+                    result.set(id, placeholder);
+                }
+            }
+        }
+
+        return result;
+    }
+
+    /**
+     * Resolve a single user ID.
+     *
+     * @param {string} id
+     * @returns {Promise<{id, username, display_name, avatar_url}>}
+     */
+    async function resolve(id) {
+        const m = await resolveMany([id]);
+        return m.get(id) || { id, username: '', display_name: '', avatar_url: '' };
+    }
+
+    /**
+     * Format a user object for display using the canonical fallback chain.
+     * Pure/synchronous — no network call.
+     *
+     * @param {object|null} user — object with display_name and/or username
+     * @returns {string}
+     */
+    function displayName(user) {
+        if (!user) return 'Unknown';
+        return user.display_name || user.username || 'Unknown';
+    }
+
+    /** Flush the cache (useful after profile updates). */
+    function clearCache() {
+        _cache.clear();
+    }
+
+    return Object.freeze({ resolve, resolveMany, displayName, clearCache });
+}
diff --git a/src/js/sw/surfaces/admin/groups.js b/src/js/sw/surfaces/admin/groups.js
index ac88a6c..6f4bad7 100644
--- a/src/js/sw/surfaces/admin/groups.js
+++ b/src/js/sw/surfaces/admin/groups.js
@@ -143,7 +143,7 @@ export default function GroupsSection() {
             <div class="admin-list">
                 ${members.map(m => html`
                     <div class="admin-surface-row" key=${m.id || m.user_id}>
-                        <span style="flex:1;">${m.username || m.user_id}</span>
+                        <span style="flex:1;">${m.display_name || m.username || 'Unknown'}</span>
                         <button class="sw-btn sw-btn--danger sw-btn--sm" onClick=${() => removeMember(m.user_id || m.id)}>Remove</button>
                     </div>
                 `)}
@@ -155,7 +155,7 @@ export default function GroupsSection() {
                             <div class="form-group"><label>User</label>
                                 <select name="userId">
                                     <option value="">Select\u2026</option>
-                                    ${allUsers.map(u => html`<option key=${u.id} value=${u.id}>${u.username}</option>`)}
+                                    ${allUsers.map(u => html`<option key=${u.id} value=${u.id}>${u.display_name || u.username}</option>`)}
                                 </select>
                             </div>
                         </div>
diff --git a/src/js/sw/surfaces/admin/teams.js b/src/js/sw/surfaces/admin/teams.js
index aeb8611..8cf61d4 100644
--- a/src/js/sw/surfaces/admin/teams.js
+++ b/src/js/sw/surfaces/admin/teams.js
@@ -106,7 +106,7 @@ export default function TeamsSection() {
             <div class="admin-list">
                 ${members.map(m => html`
                     <div class="admin-surface-row" key=${m.id}>
-                        <span style="flex:1;">${m.username || m.user_id}</span>
+                        <span style="flex:1;">${m.display_name || m.username || 'Unknown'}</span>
                         <select value=${m.role} onChange=${e => updateMemberRole(m.id, e.target.value)}
                                 style="font-size:11px;padding:2px 4px;">
                             <option value="member">member</option>
@@ -124,7 +124,7 @@ export default function TeamsSection() {
                             <div class="form-group"><label>User</label>
                                 <select name="userId">
                                     <option value="">Select user\u2026</option>
-                                    ${allUsers.map(u => html`<option key=${u.id} value=${u.id}>${u.username}</option>`)}
+                                    ${allUsers.map(u => html`<option key=${u.id} value=${u.id}>${u.display_name || u.username}</option>`)}
                                 </select>
                             </div>
                             <div class="form-group"><label>Role</label>
diff --git a/src/js/sw/surfaces/admin/users.js b/src/js/sw/surfaces/admin/users.js
index 48e03b8..9e6e23b 100644
--- a/src/js/sw/surfaces/admin/users.js
+++ b/src/js/sw/surfaces/admin/users.js
@@ -128,7 +128,8 @@ export default function UsersSection() {
                 ${filtered.map(u => html`
                     <div class="admin-surface-row" key=${u.id}>
                         <div style="flex:1;min-width:0;">
-                            <strong>${u.username}</strong>
+                            <strong>${u.display_name || u.username}</strong>
+                            <span class="text-muted" style="margin-left:8px;font-size:12px;">${u.display_name ? u.username : ''}</span>
                             <span class="text-muted" style="margin-left:8px;font-size:12px;">${u.email || ''}</span>
                             ${' '}${statusBadge(u)}
                         </div>
diff --git a/src/js/sw/surfaces/team-admin/members.js b/src/js/sw/surfaces/team-admin/members.js
index e334d67..b01f951 100644
--- a/src/js/sw/surfaces/team-admin/members.js
+++ b/src/js/sw/surfaces/team-admin/members.js
@@ -88,7 +88,7 @@ export default function MembersSection({ teamId }) {
                         <div class="form-group"><label>User</label>
                             <select name="userId">
                                 <option value="">Select\u2026</option>
-                                ${users.map(u => html`<option key=${u.id} value=${u.id}>${u.username || u.email}</option>`)}
+                                ${users.map(u => html`<option key=${u.id} value=${u.id}>${u.display_name || u.username || u.email}</option>`)}
                             </select>
                         </div>
                         <div class="form-group"><label>Role</label>
@@ -108,7 +108,7 @@ export default function MembersSection({ teamId }) {
                 ${members.length === 0 && html`<div class="empty-hint">No members</div>`}
                 ${members.map(m => html`
                     <div class="admin-surface-row" key=${m.id || m.user_id}>
-                        <strong style="flex:1;">${m.username || m.user_id}</strong>
+                        <strong style="flex:1;">${m.display_name || m.username || 'Unknown'}</strong>
                         <select value=${m.role || 'member'} style="width:100px;"
                                 onChange=${e => updateRole(m.id || m.user_id, e.target.value)}>
                             ${roles.map(r => html`<option key=${r} value=${r}>${r}</option>`)}