fix(agent): self-review fixes for archive feature

- Fix: workspace store now fetches agents with include_archived=true
  so archived agents are actually visible in the frontend (the archived
  UI was dead code before — ListAgents excludes archived by default)
- Fix: add error logging for CancelAgentTasksByAgent in ArchiveAgent
- Fix: add idempotency guards — return 409 Conflict when archiving
  an already-archived agent or restoring a non-archived agent
- Fix: revert unnecessary extra GetAgent query in ReconcileAgentStatus
  (archived agents won't have running tasks after CancelAgentTasksByAgent)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/web/features/workspace/store.ts

@@ -82,7 +82,7 @@ export const useWorkspaceStore = create<WorkspaceStore>((set, get) => ({
         toast.error("Failed to load members");
         return [] as MemberWithUser[];
       }),
-      api.listAgents({ workspace_id: nextWorkspace.id }).catch((e) => {
+      api.listAgents({ workspace_id: nextWorkspace.id, include_archived: true }).catch((e) => {
         logger.error("failed to load agents", e);
         toast.error("Failed to load agents");
         return [] as Agent[];
@@ -154,7 +154,7 @@ export const useWorkspaceStore = create<WorkspaceStore>((set, get) => ({
     const { workspace } = get();
     if (!workspace) return;
     try {
-      const agents = await api.listAgents({ workspace_id: workspace.id });
+      const agents = await api.listAgents({ workspace_id: workspace.id, include_archived: true });
       set({ agents });
     } catch (e) {
       logger.error("failed to refresh agents", e);

apps/web/shared/api/client.ts

@@ -291,10 +291,11 @@ export class ApiClient {
   }
 
   // Agents
-  async listAgents(params?: { workspace_id?: string }): Promise<Agent[]> {
+  async listAgents(params?: { workspace_id?: string; include_archived?: boolean }): Promise<Agent[]> {
     const search = new URLSearchParams();
     const wsId = params?.workspace_id ?? this.workspaceId;
     if (wsId) search.set("workspace_id", wsId);
+    if (params?.include_archived) search.set("include_archived", "true");
     return this.fetch(`/api/agents?${search}`);
   }
 

server/internal/handler/agent.go

@@ -434,6 +434,10 @@ func (h *Handler) ArchiveAgent(w http.ResponseWriter, r *http.Request) {
 	if !h.canManageAgent(w, r, agent) {
 		return
 	}
+	if agent.ArchivedAt.Valid {
+		writeError(w, http.StatusConflict, "agent is already archived")
+		return
+	}
 
 	userID := requestUserID(r)
 	archived, err := h.Queries.ArchiveAgent(r.Context(), db.ArchiveAgentParams{
@@ -447,7 +451,9 @@ func (h *Handler) ArchiveAgent(w http.ResponseWriter, r *http.Request) {
 	}
 
 	// Cancel all pending/active tasks for this agent.
-	h.Queries.CancelAgentTasksByAgent(r.Context(), parseUUID(id))
+	if err := h.Queries.CancelAgentTasksByAgent(r.Context(), parseUUID(id)); err != nil {
+		slog.Warn("cancel agent tasks on archive failed", append(logger.RequestAttrs(r), "error", err, "agent_id", id)...)
+	}
 
 	wsID := uuidToString(archived.WorkspaceID)
 	slog.Info("agent archived", append(logger.RequestAttrs(r), "agent_id", id, "workspace_id", wsID)...)
@@ -466,6 +472,10 @@ func (h *Handler) RestoreAgent(w http.ResponseWriter, r *http.Request) {
 	if !h.canManageAgent(w, r, agent) {
 		return
 	}
+	if !agent.ArchivedAt.Valid {
+		writeError(w, http.StatusConflict, "agent is not archived")
+		return
+	}
 
 	restored, err := h.Queries.RestoreAgent(r.Context(), parseUUID(id))
 	if err != nil {

server/internal/service/task.go

@@ -314,12 +314,7 @@ func (s *TaskService) ReportProgress(ctx context.Context, taskID string, workspa
 }
 
 // ReconcileAgentStatus checks running task count and sets agent status accordingly.
-// Skips archived agents — their status is irrelevant.
 func (s *TaskService) ReconcileAgentStatus(ctx context.Context, agentID pgtype.UUID) {
-	agent, err := s.Queries.GetAgent(ctx, agentID)
-	if err != nil || agent.ArchivedAt.Valid {
-		return
-	}
 	running, err := s.Queries.CountRunningTasks(ctx, agentID)
 	if err != nil {
 		return