diff --git a/internal/httpapi/server.go b/internal/httpapi/server.go
index 5d4df11..ca5cc26 100644
--- a/internal/httpapi/server.go
+++ b/internal/httpapi/server.go
@@ -61,6 +61,8 @@ func (s *Server) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		s.handleGetJob(w, r, path)
 	case r.Method == http.MethodPost && strings.HasPrefix(path, "/api/v1/jobs/") && strings.HasSuffix(path, "/retry"):
 		s.handleRetryJob(w, r, path)
+	case r.Method == http.MethodPost && strings.HasPrefix(path, "/api/v1/jobs/") && strings.HasSuffix(path, "/cancel"):
+		s.handleCancelJob(w, r, path)
 	case r.Method == http.MethodPost && strings.HasPrefix(path, "/api/v1/jobs/") && strings.HasSuffix(path, "/complete"):
 		s.handleCompleteJob(w, r, path)
 	case r.Method == http.MethodPost && strings.HasPrefix(path, "/api/v1/jobs/") && strings.HasSuffix(path, "/fail"):
@@ -267,7 +269,7 @@ func (s *Server) handleGetJob(w http.ResponseWriter, r *http.Request, path strin
 }
 
 func (s *Server) handleRetryJob(w http.ResponseWriter, r *http.Request, path string) {
-	id, err := jobIDFromPath(path, true)
+	id, err := jobIDFromActionPath(path, "retry")
 	if err != nil {
 		writeError(w, http.StatusBadRequest, err.Error())
 		return
@@ -286,6 +288,26 @@ func (s *Server) handleRetryJob(w http.ResponseWriter, r *http.Request, path str
 	writeJSON(w, http.StatusOK, job)
 }
 
+func (s *Server) handleCancelJob(w http.ResponseWriter, r *http.Request, path string) {
+	id, err := jobIDFromActionPath(path, "cancel")
+	if err != nil {
+		writeError(w, http.StatusBadRequest, err.Error())
+		return
+	}
+	ctx, cancel := contextWithTimeout(r, 8*time.Second)
+	defer cancel()
+	job, err := s.store.CancelJob(ctx, id)
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, err.Error())
+		return
+	}
+	if job == nil {
+		writeError(w, http.StatusNotFound, "cancellable job not found")
+		return
+	}
+	writeJSON(w, http.StatusOK, job)
+}
+
 func (s *Server) handleCompleteJob(w http.ResponseWriter, r *http.Request, path string) {
 	id, err := jobIDFromActionPath(path, "complete")
 	if err != nil {
diff --git a/internal/store/store.go b/internal/store/store.go
index 71563a8..965c9ac 100644
--- a/internal/store/store.go
+++ b/internal/store/store.go
@@ -451,6 +451,28 @@ WHERE j.id = picked.id
 	return int(tag.RowsAffected()), nil
 }
 
+func (s *Store) CancelJob(ctx context.Context, id uuid.UUID) (*model.Job, error) {
+	const q = `
+UPDATE ai_jobs
+SET status = 'cancelled',
+    completed_at = NOW(),
+    worker_id = NULL,
+    heartbeat_at = NULL,
+    updated_at = NOW()
+WHERE id = $1
+  AND status IN ('pending', 'running')
+RETURNING id, owner_service, owner_ref, task_type, model_profile, priority, status,
+          attempts, max_attempts, input, result, error_code, error_message,
+          scheduled_at, started_at, completed_at, worker_id, heartbeat_at,
+          created_at, updated_at, idempotency_key
+`
+	job, err := scanJob(s.pool.QueryRow(ctx, q, id))
+	if errors.Is(err, pgx.ErrNoRows) {
+		return nil, nil
+	}
+	return job, err
+}
+
 func (s *Store) CancelJobs(ctx context.Context, filter model.JobFilter) (int, error) {
 	normalizeFilter(&filter)
 	const q = `