2026-03-27 20:03:27 +00:00
6 changed files with 667 additions and 7 deletions
--- a/server/database/migrations/postgres/007_workflows.sql
+++ b/server/database/migrations/postgres/007_workflows.sql
@@ -78,3 +78,55 @@ CREATE TABLE IF NOT EXISTS workflow_versions (

 CREATE INDEX IF NOT EXISTS idx_workflow_versions_workflow
    ON workflow_versions(workflow_id, version_number DESC);
+
+-- ── Workflow Instances (v0.3.1) ──────────────
+
+CREATE TABLE IF NOT EXISTS workflow_instances (
+    id                UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    workflow_id       UUID NOT NULL REFERENCES workflows(id) ON DELETE CASCADE,
+    workflow_version  INTEGER NOT NULL,
+    current_stage     TEXT NOT NULL,
+    stage_data        JSONB NOT NULL DEFAULT '{}',
+    status            TEXT NOT NULL DEFAULT 'active'
+                          CHECK (status IN ('active', 'completed', 'cancelled', 'stale', 'error')),
+    started_by        TEXT NOT NULL,
+    entry_token       TEXT,
+    metadata          JSONB NOT NULL DEFAULT '{}',
+    stage_entered_at  TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    created_at        TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    updated_at        TIMESTAMPTZ NOT NULL DEFAULT NOW()
+);
+
+CREATE INDEX IF NOT EXISTS idx_workflow_instances_workflow_status
+    ON workflow_instances(workflow_id, status);
+CREATE INDEX IF NOT EXISTS idx_workflow_instances_active
+    ON workflow_instances(status) WHERE status = 'active';
+CREATE UNIQUE INDEX IF NOT EXISTS idx_workflow_instances_token
+    ON workflow_instances(entry_token) WHERE entry_token IS NOT NULL;
+
+DROP TRIGGER IF EXISTS workflow_instances_updated_at ON workflow_instances;
+CREATE TRIGGER workflow_instances_updated_at BEFORE UPDATE ON workflow_instances
+    FOR EACH ROW EXECUTE FUNCTION update_updated_at();
+
+-- ── Workflow Assignments (v0.3.1) ────────────
+
+CREATE TABLE IF NOT EXISTS workflow_assignments (
+    id            UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    instance_id   UUID NOT NULL REFERENCES workflow_instances(id) ON DELETE CASCADE,
+    stage         TEXT NOT NULL,
+    team_id       UUID NOT NULL REFERENCES teams(id) ON DELETE CASCADE,
+    assigned_to   UUID REFERENCES users(id) ON DELETE SET NULL,
+    status        TEXT NOT NULL DEFAULT 'unassigned'
+                      CHECK (status IN ('unassigned', 'claimed', 'completed', 'cancelled')),
+    review_data   JSONB NOT NULL DEFAULT '{}',
+    claimed_at    TIMESTAMPTZ,
+    completed_at  TIMESTAMPTZ,
+    created_at    TIMESTAMPTZ NOT NULL DEFAULT NOW()
+);
+
+CREATE INDEX IF NOT EXISTS idx_workflow_assignments_instance_stage
+    ON workflow_assignments(instance_id, stage);
+CREATE INDEX IF NOT EXISTS idx_workflow_assignments_team_status
+    ON workflow_assignments(team_id, status);
+CREATE INDEX IF NOT EXISTS idx_workflow_assignments_assigned
+    ON workflow_assignments(assigned_to) WHERE assigned_to IS NOT NULL;
--- a/server/database/migrations/sqlite/007_workflows.sql
+++ b/server/database/migrations/sqlite/007_workflows.sql
@@ -69,3 +69,53 @@ CREATE TABLE IF NOT EXISTS workflow_versions (

 CREATE INDEX IF NOT EXISTS idx_workflow_versions_workflow
    ON workflow_versions(workflow_id, version_number);
+
+-- ── Workflow Instances (v0.3.1) ──────────────
+
+CREATE TABLE IF NOT EXISTS workflow_instances (
+    id                TEXT PRIMARY KEY,
+    workflow_id       TEXT NOT NULL REFERENCES workflows(id) ON DELETE CASCADE,
+    workflow_version  INTEGER NOT NULL,
+    current_stage     TEXT NOT NULL,
+    stage_data        TEXT NOT NULL DEFAULT '{}',
+    status            TEXT NOT NULL DEFAULT 'active'
+                          CHECK (status IN ('active', 'completed', 'cancelled', 'stale', 'error')),
+    started_by        TEXT NOT NULL,
+    entry_token       TEXT UNIQUE,
+    metadata          TEXT NOT NULL DEFAULT '{}',
+    stage_entered_at  TEXT NOT NULL DEFAULT (datetime('now')),
+    created_at        TEXT NOT NULL DEFAULT (datetime('now')),
+    updated_at        TEXT NOT NULL DEFAULT (datetime('now'))
+);
+
+CREATE INDEX IF NOT EXISTS idx_workflow_instances_workflow_status
+    ON workflow_instances(workflow_id, status);
+CREATE INDEX IF NOT EXISTS idx_workflow_instances_active
+    ON workflow_instances(status);
+
+CREATE TRIGGER IF NOT EXISTS workflow_instances_updated_at AFTER UPDATE ON workflow_instances
+    FOR EACH ROW WHEN NEW.updated_at = OLD.updated_at
+    BEGIN UPDATE workflow_instances SET updated_at = datetime('now') WHERE id = NEW.id; END;
+
+-- ── Workflow Assignments (v0.3.1) ────────────
+
+CREATE TABLE IF NOT EXISTS workflow_assignments (
+    id            TEXT PRIMARY KEY,
+    instance_id   TEXT NOT NULL REFERENCES workflow_instances(id) ON DELETE CASCADE,
+    stage         TEXT NOT NULL,
+    team_id       TEXT NOT NULL REFERENCES teams(id) ON DELETE CASCADE,
+    assigned_to   TEXT REFERENCES users(id) ON DELETE SET NULL,
+    status        TEXT NOT NULL DEFAULT 'unassigned'
+                      CHECK (status IN ('unassigned', 'claimed', 'completed', 'cancelled')),
+    review_data   TEXT NOT NULL DEFAULT '{}',
+    claimed_at    TEXT,
+    completed_at  TEXT,
+    created_at    TEXT NOT NULL DEFAULT (datetime('now'))
+);
+
+CREATE INDEX IF NOT EXISTS idx_workflow_assignments_instance_stage
+    ON workflow_assignments(instance_id, stage);
+CREATE INDEX IF NOT EXISTS idx_workflow_assignments_team_status
+    ON workflow_assignments(team_id, status);
+CREATE INDEX IF NOT EXISTS idx_workflow_assignments_assigned
+    ON workflow_assignments(assigned_to);
--- a/server/models/workflow.go
+++ b/server/models/workflow.go
@@ -432,6 +432,76 @@ func evaluateFieldCondition(cond *FieldCondition, data map[string]interface{}) b
 	}
 }

+// ── Instance Status Constants ───────────────
+
+const (
+	InstanceStatusActive    = "active"
+	InstanceStatusCompleted = "completed"
+	InstanceStatusCancelled = "cancelled"
+	InstanceStatusStale     = "stale"
+	InstanceStatusError     = "error"
+)
+
+// ValidInstanceStatuses is the set of valid workflow instance status values.
+var ValidInstanceStatuses = map[string]bool{
+	InstanceStatusActive:    true,
+	InstanceStatusCompleted: true,
+	InstanceStatusCancelled: true,
+	InstanceStatusStale:     true,
+	InstanceStatusError:     true,
+}
+
+// ── Assignment Status Constants ─────────────
+
+const (
+	AssignmentStatusUnassigned = "unassigned"
+	AssignmentStatusClaimed    = "claimed"
+	AssignmentStatusCompleted  = "completed"
+	AssignmentStatusCancelled  = "cancelled"
+)
+
+// ValidAssignmentStatuses is the set of valid workflow assignment status values.
+var ValidAssignmentStatuses = map[string]bool{
+	AssignmentStatusUnassigned: true,
+	AssignmentStatusClaimed:    true,
+	AssignmentStatusCompleted:  true,
+	AssignmentStatusCancelled:  true,
+}
+
+// ── Workflow Instance ───────────────────────
+
+// WorkflowInstance tracks a single execution of a workflow definition.
+type WorkflowInstance struct {
+	ID              string          `json:"id"`
+	WorkflowID      string          `json:"workflow_id"`
+	WorkflowVersion int             `json:"workflow_version"`
+	CurrentStage    string          `json:"current_stage"`
+	StageData       json.RawMessage `json:"stage_data"`
+	Status          string          `json:"status"`
+	StartedBy       string          `json:"started_by"`
+	EntryToken      *string         `json:"entry_token,omitempty"`
+	Metadata        json.RawMessage `json:"metadata"`
+	StageEnteredAt  time.Time       `json:"stage_entered_at"`
+	CreatedAt       time.Time       `json:"created_at"`
+	UpdatedAt       time.Time       `json:"updated_at"`
+}
+
+// ── Workflow Assignment ─────────────────────
+
+// WorkflowAssignment tracks per-stage work items in the team queue.
+type WorkflowAssignment struct {
+	ID          string          `json:"id"`
+	InstanceID  string          `json:"instance_id"`
+	Stage       string          `json:"stage"`
+	TeamID      string          `json:"team_id"`
+	AssignedTo  *string         `json:"assigned_to,omitempty"`
+	Status      string          `json:"status"`
+	ReviewData  json.RawMessage `json:"review_data"`
+	ClaimedAt   *time.Time      `json:"claimed_at,omitempty"`
+	CompletedAt *time.Time      `json:"completed_at,omitempty"`
+	CreatedAt   time.Time       `json:"created_at"`
+}
+
 // ── Workflow Version (immutable snapshot) ───

 // WorkflowVersion is an immutable snapshot of a workflow definition
--- a/server/store/postgres/workflows.go
+++ b/server/store/postgres/workflows.go
@@ -6,6 +6,7 @@ import (
 	"fmt"

 	"switchboard-core/models"
+	"switchboard-core/store"
 )

 // WorkflowStore implements store.WorkflowStore for Postgres.
@@ -396,8 +397,235 @@ func nullIfEmpty(s string) interface{} {
 	return s
 }

-// ── Assignments (v0.29.0-cs3) ───────────────────────────────────────────
+// ── Instances (v0.3.1) ──────────────────────

-// ── Lifecycle operations (v0.37.15) ──
+func (s *WorkflowStore) CreateInstance(ctx context.Context, inst *models.WorkflowInstance) error {
+	stageData := jsonOrEmpty(inst.StageData)
+	metadata := jsonOrEmpty(inst.Metadata)
+	status := inst.Status
+	if status == "" {
+		status = models.InstanceStatusActive
+	}
+	return DB.QueryRowContext(ctx, `
+		INSERT INTO workflow_instances (workflow_id, workflow_version, current_stage,
+		            stage_data, status, started_by, entry_token, metadata)
+		VALUES ($1, $2, $3, $4, $5, $6, $7, $8)
+		RETURNING id, stage_entered_at, created_at, updated_at`,
+		inst.WorkflowID, inst.WorkflowVersion, inst.CurrentStage,
+		stageData, status, inst.StartedBy, inst.EntryToken, metadata,
+	).Scan(&inst.ID, &inst.StageEnteredAt, &inst.CreatedAt, &inst.UpdatedAt)
+}

-// ── Review Comments (v0.35.0) ───────────────────────────
+func (s *WorkflowStore) GetInstance(ctx context.Context, id string) (*models.WorkflowInstance, error) {
+	inst := &models.WorkflowInstance{}
+	var stageData, metadata []byte
+	err := DB.QueryRowContext(ctx, `
+		SELECT id, workflow_id, workflow_version, current_stage, stage_data,
+		       status, started_by, entry_token, metadata,
+		       stage_entered_at, created_at, updated_at
+		FROM workflow_instances WHERE id = $1`, id,
+	).Scan(&inst.ID, &inst.WorkflowID, &inst.WorkflowVersion, &inst.CurrentStage,
+		&stageData, &inst.Status, &inst.StartedBy, &inst.EntryToken, &metadata,
+		&inst.StageEnteredAt, &inst.CreatedAt, &inst.UpdatedAt)
+	if err != nil {
+		return nil, err
+	}
+	inst.StageData = stageData
+	inst.Metadata = metadata
+	return inst, nil
+}
+
+func (s *WorkflowStore) GetInstanceByToken(ctx context.Context, token string) (*models.WorkflowInstance, error) {
+	inst := &models.WorkflowInstance{}
+	var stageData, metadata []byte
+	err := DB.QueryRowContext(ctx, `
+		SELECT id, workflow_id, workflow_version, current_stage, stage_data,
+		       status, started_by, entry_token, metadata,
+		       stage_entered_at, created_at, updated_at
+		FROM workflow_instances WHERE entry_token = $1`, token,
+	).Scan(&inst.ID, &inst.WorkflowID, &inst.WorkflowVersion, &inst.CurrentStage,
+		&stageData, &inst.Status, &inst.StartedBy, &inst.EntryToken, &metadata,
+		&inst.StageEnteredAt, &inst.CreatedAt, &inst.UpdatedAt)
+	if err != nil {
+		return nil, err
+	}
+	inst.StageData = stageData
+	inst.Metadata = metadata
+	return inst, nil
+}
+
+func (s *WorkflowStore) UpdateInstance(ctx context.Context, inst *models.WorkflowInstance) error {
+	stageData := jsonOrEmpty(inst.StageData)
+	metadata := jsonOrEmpty(inst.Metadata)
+	_, err := DB.ExecContext(ctx, `
+		UPDATE workflow_instances
+		SET current_stage = $2, stage_data = $3, status = $4,
+		    entry_token = $5, metadata = $6, stage_entered_at = $7
+		WHERE id = $1`,
+		inst.ID, inst.CurrentStage, stageData, inst.Status,
+		inst.EntryToken, metadata, inst.StageEnteredAt)
+	return err
+}
+
+func (s *WorkflowStore) ListInstances(ctx context.Context, workflowID string, status string, opts store.ListOptions) ([]models.WorkflowInstance, error) {
+	q := `SELECT id, workflow_id, workflow_version, current_stage, stage_data,
+	             status, started_by, entry_token, metadata,
+	             stage_entered_at, created_at, updated_at
+	      FROM workflow_instances WHERE workflow_id = $1`
+	args := []interface{}{workflowID}
+	idx := 2
+	if status != "" {
+		q += fmt.Sprintf(" AND status = $%d", idx)
+		args = append(args, status)
+		idx++
+	}
+	q += " ORDER BY created_at DESC"
+	if opts.Limit > 0 {
+		q += fmt.Sprintf(" LIMIT $%d", idx)
+		args = append(args, opts.Limit)
+		idx++
+	}
+	if opts.Offset > 0 {
+		q += fmt.Sprintf(" OFFSET $%d", idx)
+		args = append(args, opts.Offset)
+	}
+	rows, err := DB.QueryContext(ctx, q, args...)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	var result []models.WorkflowInstance
+	for rows.Next() {
+		var inst models.WorkflowInstance
+		var stageData, metadata []byte
+		if err := rows.Scan(&inst.ID, &inst.WorkflowID, &inst.WorkflowVersion,
+			&inst.CurrentStage, &stageData, &inst.Status, &inst.StartedBy,
+			&inst.EntryToken, &metadata,
+			&inst.StageEnteredAt, &inst.CreatedAt, &inst.UpdatedAt); err != nil {
+			return nil, err
+		}
+		inst.StageData = stageData
+		inst.Metadata = metadata
+		result = append(result, inst)
+	}
+	return result, rows.Err()
+}
+
+func (s *WorkflowStore) AdvanceStage(ctx context.Context, id string, nextStage string, stageData json.RawMessage) error {
+	sd := jsonOrEmpty(stageData)
+	_, err := DB.ExecContext(ctx, `
+		UPDATE workflow_instances
+		SET current_stage = $2, stage_data = $3, stage_entered_at = NOW()
+		WHERE id = $1 AND status = 'active'`,
+		id, nextStage, sd)
+	return err
+}
+
+func (s *WorkflowStore) CompleteInstance(ctx context.Context, id string) error {
+	_, err := DB.ExecContext(ctx, `
+		UPDATE workflow_instances SET status = 'completed' WHERE id = $1 AND status = 'active'`, id)
+	return err
+}
+
+func (s *WorkflowStore) CancelInstance(ctx context.Context, id string) error {
+	_, err := DB.ExecContext(ctx, `
+		UPDATE workflow_instances SET status = 'cancelled' WHERE id = $1 AND status = 'active'`, id)
+	return err
+}
+
+// ── Assignments (v0.3.1) ────────────────────
+
+func (s *WorkflowStore) CreateAssignment(ctx context.Context, a *models.WorkflowAssignment) error {
+	reviewData := jsonOrEmpty(a.ReviewData)
+	status := a.Status
+	if status == "" {
+		status = models.AssignmentStatusUnassigned
+	}
+	return DB.QueryRowContext(ctx, `
+		INSERT INTO workflow_assignments (instance_id, stage, team_id, assigned_to, status, review_data)
+		VALUES ($1, $2, $3, $4, $5, $6)
+		RETURNING id, created_at`,
+		a.InstanceID, a.Stage, a.TeamID, a.AssignedTo, status, reviewData,
+	).Scan(&a.ID, &a.CreatedAt)
+}
+
+func (s *WorkflowStore) ClaimAssignment(ctx context.Context, id string, userID string) error {
+	res, err := DB.ExecContext(ctx, `
+		UPDATE workflow_assignments
+		SET status = 'claimed', assigned_to = $2, claimed_at = NOW()
+		WHERE id = $1 AND status = 'unassigned'`, id, userID)
+	if err != nil {
+		return err
+	}
+	n, _ := res.RowsAffected()
+	if n == 0 {
+		return fmt.Errorf("assignment %s is not claimable", id)
+	}
+	return nil
+}
+
+func (s *WorkflowStore) UnclaimAssignment(ctx context.Context, id string) error {
+	_, err := DB.ExecContext(ctx, `
+		UPDATE workflow_assignments
+		SET status = 'unassigned', assigned_to = NULL, claimed_at = NULL
+		WHERE id = $1 AND status = 'claimed'`, id)
+	return err
+}
+
+func (s *WorkflowStore) CompleteAssignment(ctx context.Context, id string, reviewData json.RawMessage) error {
+	rd := jsonOrEmpty(reviewData)
+	_, err := DB.ExecContext(ctx, `
+		UPDATE workflow_assignments
+		SET status = 'completed', review_data = $2, completed_at = NOW()
+		WHERE id = $1 AND status = 'claimed'`, id, rd)
+	return err
+}
+
+func (s *WorkflowStore) CancelAssignment(ctx context.Context, id string) error {
+	_, err := DB.ExecContext(ctx, `
+		UPDATE workflow_assignments SET status = 'cancelled'
+		WHERE id = $1 AND status IN ('unassigned', 'claimed')`, id)
+	return err
+}
+
+func (s *WorkflowStore) ListAssignmentsByTeam(ctx context.Context, teamID string, status string) ([]models.WorkflowAssignment, error) {
+	q := `SELECT id, instance_id, stage, team_id, assigned_to, status,
+	             review_data, claimed_at, completed_at, created_at
+	      FROM workflow_assignments WHERE team_id = $1`
+	args := []interface{}{teamID}
+	if status != "" {
+		q += " AND status = $2"
+		args = append(args, status)
+	}
+	q += " ORDER BY created_at DESC"
+	return s.queryAssignments(ctx, q, args...)
+}
+
+func (s *WorkflowStore) ListAssignmentsByInstance(ctx context.Context, instanceID string) ([]models.WorkflowAssignment, error) {
+	return s.queryAssignments(ctx, `
+		SELECT id, instance_id, stage, team_id, assigned_to, status,
+		       review_data, claimed_at, completed_at, created_at
+		FROM workflow_assignments WHERE instance_id = $1
+		ORDER BY created_at ASC`, instanceID)
+}
+
+func (s *WorkflowStore) queryAssignments(ctx context.Context, q string, args ...interface{}) ([]models.WorkflowAssignment, error) {
+	rows, err := DB.QueryContext(ctx, q, args...)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	var result []models.WorkflowAssignment
+	for rows.Next() {
+		var a models.WorkflowAssignment
+		var reviewData []byte
+		if err := rows.Scan(&a.ID, &a.InstanceID, &a.Stage, &a.TeamID,
+			&a.AssignedTo, &a.Status, &reviewData,
+			&a.ClaimedAt, &a.CompletedAt, &a.CreatedAt); err != nil {
+			return nil, err
+		}
+		a.ReviewData = reviewData
+		result = append(result, a)
+	}
+	return result, rows.Err()
+}
--- a/server/store/sqlite/workflows.go
+++ b/server/store/sqlite/workflows.go
@@ -4,6 +4,7 @@ import (
 	"context"
 	"database/sql"
 	"encoding/json"
+	"fmt"
 	"time"

 	"switchboard-core/models"
@@ -409,8 +410,246 @@ func nullIfEmpty(s string) interface{} {
 	return s
 }

-// ── Assignments (v0.29.0-cs3) ───────────────────────────────────────────
+// ── Instances (v0.3.1) ──────────────────────

-// ── Lifecycle operations (v0.37.15) ──
+func (s *WorkflowStore) CreateInstance(ctx context.Context, inst *models.WorkflowInstance) error {
+	inst.ID = store.NewID()
+	now := time.Now().UTC()
+	inst.CreatedAt = now
+	inst.UpdatedAt = now
+	inst.StageEnteredAt = now
+	if inst.Status == "" {
+		inst.Status = models.InstanceStatusActive
+	}
+	stageData := jsonOrEmpty(inst.StageData)
+	metadata := jsonOrEmpty(inst.Metadata)
+	_, err := DB.ExecContext(ctx, `
+		INSERT INTO workflow_instances (id, workflow_id, workflow_version, current_stage,
+		            stage_data, status, started_by, entry_token, metadata,
+		            stage_entered_at, created_at, updated_at)
+		VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)`,
+		inst.ID, inst.WorkflowID, inst.WorkflowVersion, inst.CurrentStage,
+		stageData, inst.Status, inst.StartedBy, inst.EntryToken, metadata,
+		inst.StageEnteredAt.Format(timeFmt), inst.CreatedAt.Format(timeFmt),
+		inst.UpdatedAt.Format(timeFmt))
+	return err
+}

-// ── Review Comments (v0.35.0) ───────────────────────────
+func (s *WorkflowStore) GetInstance(ctx context.Context, id string) (*models.WorkflowInstance, error) {
+	return s.scanInstance(ctx, `
+		SELECT id, workflow_id, workflow_version, current_stage, stage_data,
+		       status, started_by, entry_token, metadata,
+		       stage_entered_at, created_at, updated_at
+		FROM workflow_instances WHERE id = ?`, id)
+}
+
+func (s *WorkflowStore) GetInstanceByToken(ctx context.Context, token string) (*models.WorkflowInstance, error) {
+	return s.scanInstance(ctx, `
+		SELECT id, workflow_id, workflow_version, current_stage, stage_data,
+		       status, started_by, entry_token, metadata,
+		       stage_entered_at, created_at, updated_at
+		FROM workflow_instances WHERE entry_token = ?`, token)
+}
+
+func (s *WorkflowStore) scanInstance(ctx context.Context, q string, args ...interface{}) (*models.WorkflowInstance, error) {
+	inst := &models.WorkflowInstance{}
+	var stageData, metadata string
+	err := DB.QueryRowContext(ctx, q, args...).Scan(
+		&inst.ID, &inst.WorkflowID, &inst.WorkflowVersion, &inst.CurrentStage,
+		&stageData, &inst.Status, &inst.StartedBy, &inst.EntryToken, &metadata,
+		st(&inst.StageEnteredAt), st(&inst.CreatedAt), st(&inst.UpdatedAt))
+	if err != nil {
+		return nil, err
+	}
+	inst.StageData = json.RawMessage(stageData)
+	inst.Metadata = json.RawMessage(metadata)
+	return inst, nil
+}
+
+func (s *WorkflowStore) UpdateInstance(ctx context.Context, inst *models.WorkflowInstance) error {
+	stageData := jsonOrEmpty(inst.StageData)
+	metadata := jsonOrEmpty(inst.Metadata)
+	now := time.Now().UTC()
+	_, err := DB.ExecContext(ctx, `
+		UPDATE workflow_instances
+		SET current_stage = ?, stage_data = ?, status = ?,
+		    entry_token = ?, metadata = ?, stage_entered_at = ?,
+		    updated_at = ?
+		WHERE id = ?`,
+		inst.CurrentStage, stageData, inst.Status,
+		inst.EntryToken, metadata, inst.StageEnteredAt.Format(timeFmt),
+		now.Format(timeFmt), inst.ID)
+	if err == nil {
+		inst.UpdatedAt = now
+	}
+	return err
+}
+
+func (s *WorkflowStore) ListInstances(ctx context.Context, workflowID string, status string, opts store.ListOptions) ([]models.WorkflowInstance, error) {
+	q := `SELECT id, workflow_id, workflow_version, current_stage, stage_data,
+	             status, started_by, entry_token, metadata,
+	             stage_entered_at, created_at, updated_at
+	      FROM workflow_instances WHERE workflow_id = ?`
+	args := []interface{}{workflowID}
+	if status != "" {
+		q += " AND status = ?"
+		args = append(args, status)
+	}
+	q += " ORDER BY created_at DESC"
+	if opts.Limit > 0 {
+		q += " LIMIT ?"
+		args = append(args, opts.Limit)
+	}
+	if opts.Offset > 0 {
+		q += " OFFSET ?"
+		args = append(args, opts.Offset)
+	}
+	rows, err := DB.QueryContext(ctx, q, args...)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	var result []models.WorkflowInstance
+	for rows.Next() {
+		var inst models.WorkflowInstance
+		var stageData, metadata string
+		if err := rows.Scan(&inst.ID, &inst.WorkflowID, &inst.WorkflowVersion,
+			&inst.CurrentStage, &stageData, &inst.Status, &inst.StartedBy,
+			&inst.EntryToken, &metadata,
+			st(&inst.StageEnteredAt), st(&inst.CreatedAt), st(&inst.UpdatedAt)); err != nil {
+			return nil, err
+		}
+		inst.StageData = json.RawMessage(stageData)
+		inst.Metadata = json.RawMessage(metadata)
+		result = append(result, inst)
+	}
+	return result, rows.Err()
+}
+
+func (s *WorkflowStore) AdvanceStage(ctx context.Context, id string, nextStage string, stageData json.RawMessage) error {
+	sd := jsonOrEmpty(stageData)
+	now := time.Now().UTC()
+	_, err := DB.ExecContext(ctx, `
+		UPDATE workflow_instances
+		SET current_stage = ?, stage_data = ?, stage_entered_at = ?, updated_at = ?
+		WHERE id = ? AND status = 'active'`,
+		nextStage, sd, now.Format(timeFmt), now.Format(timeFmt), id)
+	return err
+}
+
+func (s *WorkflowStore) CompleteInstance(ctx context.Context, id string) error {
+	now := time.Now().UTC()
+	_, err := DB.ExecContext(ctx, `
+		UPDATE workflow_instances SET status = 'completed', updated_at = ?
+		WHERE id = ? AND status = 'active'`, now.Format(timeFmt), id)
+	return err
+}
+
+func (s *WorkflowStore) CancelInstance(ctx context.Context, id string) error {
+	now := time.Now().UTC()
+	_, err := DB.ExecContext(ctx, `
+		UPDATE workflow_instances SET status = 'cancelled', updated_at = ?
+		WHERE id = ? AND status = 'active'`, now.Format(timeFmt), id)
+	return err
+}
+
+// ── Assignments (v0.3.1) ────────────────────
+
+func (s *WorkflowStore) CreateAssignment(ctx context.Context, a *models.WorkflowAssignment) error {
+	a.ID = store.NewID()
+	a.CreatedAt = time.Now().UTC()
+	if a.Status == "" {
+		a.Status = models.AssignmentStatusUnassigned
+	}
+	reviewData := jsonOrEmpty(a.ReviewData)
+	_, err := DB.ExecContext(ctx, `
+		INSERT INTO workflow_assignments (id, instance_id, stage, team_id, assigned_to,
+		            status, review_data, claimed_at, completed_at, created_at)
+		VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)`,
+		a.ID, a.InstanceID, a.Stage, a.TeamID, a.AssignedTo,
+		a.Status, reviewData, nil, nil, a.CreatedAt.Format(timeFmt))
+	return err
+}
+
+func (s *WorkflowStore) ClaimAssignment(ctx context.Context, id string, userID string) error {
+	now := time.Now().UTC()
+	res, err := DB.ExecContext(ctx, `
+		UPDATE workflow_assignments
+		SET status = 'claimed', assigned_to = ?, claimed_at = ?
+		WHERE id = ? AND status = 'unassigned'`, userID, now.Format(timeFmt), id)
+	if err != nil {
+		return err
+	}
+	n, _ := res.RowsAffected()
+	if n == 0 {
+		return fmt.Errorf("assignment %s is not claimable", id)
+	}
+	return nil
+}
+
+func (s *WorkflowStore) UnclaimAssignment(ctx context.Context, id string) error {
+	_, err := DB.ExecContext(ctx, `
+		UPDATE workflow_assignments
+		SET status = 'unassigned', assigned_to = NULL, claimed_at = NULL
+		WHERE id = ? AND status = 'claimed'`, id)
+	return err
+}
+
+func (s *WorkflowStore) CompleteAssignment(ctx context.Context, id string, reviewData json.RawMessage) error {
+	rd := jsonOrEmpty(reviewData)
+	now := time.Now().UTC()
+	_, err := DB.ExecContext(ctx, `
+		UPDATE workflow_assignments
+		SET status = 'completed', review_data = ?, completed_at = ?
+		WHERE id = ? AND status = 'claimed'`, rd, now.Format(timeFmt), id)
+	return err
+}
+
+func (s *WorkflowStore) CancelAssignment(ctx context.Context, id string) error {
+	_, err := DB.ExecContext(ctx, `
+		UPDATE workflow_assignments SET status = 'cancelled'
+		WHERE id = ? AND status IN ('unassigned', 'claimed')`, id)
+	return err
+}
+
+func (s *WorkflowStore) ListAssignmentsByTeam(ctx context.Context, teamID string, status string) ([]models.WorkflowAssignment, error) {
+	q := `SELECT id, instance_id, stage, team_id, assigned_to, status,
+	             review_data, claimed_at, completed_at, created_at
+	      FROM workflow_assignments WHERE team_id = ?`
+	args := []interface{}{teamID}
+	if status != "" {
+		q += " AND status = ?"
+		args = append(args, status)
+	}
+	q += " ORDER BY created_at DESC"
+	return s.queryAssignments(ctx, q, args...)
+}
+
+func (s *WorkflowStore) ListAssignmentsByInstance(ctx context.Context, instanceID string) ([]models.WorkflowAssignment, error) {
+	return s.queryAssignments(ctx, `
+		SELECT id, instance_id, stage, team_id, assigned_to, status,
+		       review_data, claimed_at, completed_at, created_at
+		FROM workflow_assignments WHERE instance_id = ?
+		ORDER BY created_at ASC`, instanceID)
+}
+
+func (s *WorkflowStore) queryAssignments(ctx context.Context, q string, args ...interface{}) ([]models.WorkflowAssignment, error) {
+	rows, err := DB.QueryContext(ctx, q, args...)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	var result []models.WorkflowAssignment
+	for rows.Next() {
+		var a models.WorkflowAssignment
+		var reviewData string
+		if err := rows.Scan(&a.ID, &a.InstanceID, &a.Stage, &a.TeamID,
+			&a.AssignedTo, &a.Status, &reviewData,
+			stN(&a.ClaimedAt), stN(&a.CompletedAt), st(&a.CreatedAt)); err != nil {
+			return nil, err
+		}
+		a.ReviewData = json.RawMessage(reviewData)
+		result = append(result, a)
+	}
+	return result, rows.Err()
+}
--- a/server/store/workflow_iface.go
+++ b/server/store/workflow_iface.go
@@ -2,11 +2,13 @@ package store

 import (
 	"context"
+	"encoding/json"

 	"switchboard-core/models"
 )

-// WorkflowStore manages workflow definitions, stages, and version snapshots.
+// WorkflowStore manages workflow definitions, stages, version snapshots,
+// instances, and assignments.
 type WorkflowStore interface {
 	// Workflow CRUD
 	Create(ctx context.Context, w *models.Workflow) error
@@ -28,4 +30,23 @@ type WorkflowStore interface {
 	Publish(ctx context.Context, v *models.WorkflowVersion) error
 	GetVersion(ctx context.Context, workflowID string, versionNumber int) (*models.WorkflowVersion, error)
 	GetLatestVersion(ctx context.Context, workflowID string) (*models.WorkflowVersion, error)
+
+	// Instances (v0.3.1)
+	CreateInstance(ctx context.Context, inst *models.WorkflowInstance) error
+	GetInstance(ctx context.Context, id string) (*models.WorkflowInstance, error)
+	GetInstanceByToken(ctx context.Context, token string) (*models.WorkflowInstance, error)
+	UpdateInstance(ctx context.Context, inst *models.WorkflowInstance) error
+	ListInstances(ctx context.Context, workflowID string, status string, opts ListOptions) ([]models.WorkflowInstance, error)
+	AdvanceStage(ctx context.Context, id string, nextStage string, stageData json.RawMessage) error
+	CompleteInstance(ctx context.Context, id string) error
+	CancelInstance(ctx context.Context, id string) error
+
+	// Assignments (v0.3.1)
+	CreateAssignment(ctx context.Context, a *models.WorkflowAssignment) error
+	ClaimAssignment(ctx context.Context, id string, userID string) error
+	UnclaimAssignment(ctx context.Context, id string) error
+	CompleteAssignment(ctx context.Context, id string, reviewData json.RawMessage) error
+	CancelAssignment(ctx context.Context, id string) error
+	ListAssignmentsByTeam(ctx context.Context, teamID string, status string) ([]models.WorkflowAssignment, error)
+	ListAssignmentsByInstance(ctx context.Context, instanceID string) ([]models.WorkflowAssignment, error)
 }