stack/docs/reports/codebase-review-2026-02-05/02-code-quality-review.md

Mosaic Stack - Code Quality Review

Date: 2026-02-05 Reviewers: 3 parallel code quality analysis agents Total Findings: 29 (11 Critical/High, 8 Medium, 10 Low/Code Smell)

---

apps/api - Code Quality (7 Findings)

CQ-API-1: Memory Leak - setTimeout Not Cleared in WebSocket Gateway [HIGH]

• File: apps/api/src/websocket/websocket.gateway.ts:105-166
• Issue: If workspaceMembership query throws, timeoutId is never cleared. Each failed connection leaks a timer.
• Fix: Call clearTimeout(timeoutId) in catch block at line 159.

CQ-API-2: Memory Leak - setInterval Not Cleared in Runner Jobs [HIGH]

• File: apps/api/src/runner-jobs/runner-jobs.service.ts:310-449
• Issue: keepAliveInterval at line 315 is never explicitly cleared with clearInterval().
• Fix: Add clearInterval(keepAliveInterval) in the finally block.

CQ-API-3: Activity Logging Re-Throws (Defeats Fire-and-Forget) [MEDIUM]

• File: apps/api/src/activity/activity.service.ts:23-31
• Issue: logActivity catches errors, logs them, then re-throws. Activity logging failures break primary operations.
• Fix: Make fire-and-forget (don't re-throw) or document that callers must handle.

CQ-API-4: Missing Cleanup for Redis Event Listeners [MEDIUM]

• File: apps/api/src/valkey/valkey.service.ts:43-53
• Issue: Event listeners registered on Redis client but never removed in onModuleDestroy.
• Fix: Call this.client.removeAllListeners() before quit() in onModuleDestroy.

CQ-API-5: Race Condition in Throttler Fallback Storage [LOW]

• File: apps/api/src/common/throttler/throttler-storage.service.ts:140-154
• Issue: In-memory fallback incrementMemory has non-atomic read-modify-write.
• Fix: Use mutex/lock, or document in-memory mode as best-effort.

CQ-API-6: Hardcoded TODO Values in OIDC Federation [CRITICAL]

• File: apps/api/src/federation/oidc.service.ts:140-141
• Issue: JWT validation uses hardcoded "https://auth.example.com" and "mosaic-client-id".
• Fix: Load from environment variables. Fail fast if unconfigured.

CQ-API-7: N+1 Query in Knowledge Service Tag Lookup [LOW]

• File: apps/api/src/knowledge/knowledge.service.ts:817-827
• Issue: Promise.all with individual findFirst queries per tag name.
• Fix: Replace with single findMany WHERE name IN tagNames.

---

apps/web - Code Quality (12 Findings)

CQ-WEB-1: Stale Closure in useWebSocket Hook [CRITICAL]

• File: apps/web/src/hooks/useWebSocket.ts:127-137
• Issue: Callback functions in useEffect deps cause WebSocket disconnect/reconnect on every parent re-render.
• Fix: Use refs for callbacks. Only include stable values (workspaceId, token) in deps.

CQ-WEB-2: Missing Dependency in FilterBar useEffect [HIGH]

• File: apps/web/src/components/filters/FilterBar.tsx:33-50
• Issue: useEffect accesses filters and onFilterChange but they're not in the dependency array.
• Fix: Add missing dependencies or use functional updates.

CQ-WEB-3: Race Condition in LinkAutocomplete [HIGH]

• File: apps/web/src/components/knowledge/LinkAutocomplete.tsx:96-107
• Issue: Debounced search doesn't cancel in-flight requests. Older results can overwrite newer ones.
• Fix: Use AbortController to cancel in-flight requests.

CQ-WEB-4: Stale Messages in useChat Hook [CRITICAL]

• File: apps/web/src/hooks/useChat.ts:146-236
• Issue: sendMessage captures messages in closure. Rapid sends use stale state. Data loss.
• Fix: Use functional state updates: setMessages(prev => [...prev, userMessage]).

CQ-WEB-5: Incorrect Boolean Logic in ReactFlowEditor [CRITICAL]

• File: apps/web/src/components/mindmap/ReactFlowEditor.tsx:213-214
• Issue: readOnly ?? !selectedNode should be readOnly || !selectedNode. The ?? operator with boolean never evaluates right side when readOnly is false.
• Fix: Change ?? to ||.

CQ-WEB-6: Memory Leak in Chat Component Timers [MEDIUM]

• File: apps/web/src/components/chat/Chat.tsx:146-174
• Issue: Timer cleanup structure is confusing and may leak in edge cases.
• Fix: Restructure to only create timers when isChatLoading is true with proper cleanup.

CQ-WEB-7: KanbanBoard No UI Revert on Error [CRITICAL]

• File: apps/web/src/components/kanban/KanbanBoard.tsx:97-117
• Issue: PATCH error logged but UI not reverted. User sees task in wrong column.
• Fix: Implement optimistic updates with rollback on error.

CQ-WEB-8: No React.memo Usage Anywhere [PERFORMANCE]

• Files: All component files
• Issue: Zero components use React.memo despite 115+ uses of useMemo/useCallback and large lists.
• Fix: Wrap pure components in React.memo (TaskItem, KanbanColumn, etc.).

CQ-WEB-9: DOM Manipulation in LinkAutocomplete [PERFORMANCE]

• File: apps/web/src/components/knowledge/LinkAutocomplete.tsx:112-165
• Issue: Creates temporary DOM element on every position calculation, causing layout thrashing.
• Fix: Use textarea-caret-position library or cached measurement.

CQ-WEB-10: Missing Loading States on Many Pages [CODE SMELL]

• Files: tasks/page.tsx, calendar/page.tsx, multiple federation pages
• Issue: Pages use mock data with TODO comments. No loading states.
• Fix: Implement loading/error states even with mock data.

CQ-WEB-11: Accessibility - Missing Form Labels [ACCESSIBILITY]

• File: apps/web/src/components/filters/FilterBar.tsx:115-188
• Issue: Checkboxes lack proper label associations for screen readers.
• Fix: Add explicit id/htmlFor or aria-label.

CQ-WEB-12: SSR Issue - Window Check After DOM Usage [BUG]

• File: apps/web/src/components/mindmap/ReactFlowEditor.tsx:238-245
• Issue: Checks typeof window after already using document.addEventListener.
• Fix: Use useEffect for all DOM access. Consistently check typeof window.

---

apps/orchestrator - Code Quality (10 Findings)

CQ-ORCH-1: Memory Leak - Agent Sessions Never Cleaned Up [CRITICAL]

• File: apps/orchestrator/src/spawner/agent-spawner.service.ts:19
• Issue: Sessions Map never has entries removed. No cleanup on terminal states.
• Fix: Add session cleanup after completed/failed/killed transitions.

CQ-ORCH-2: Race Condition - Dual State Management [HIGH]

• File: apps/orchestrator/src/api/agents/agents.controller.ts:91-118
• Issue: Two sources of truth (in-memory Map + Valkey). Can get out of sync during rapid transitions.
• Fix: Use Valkey as single source of truth. Remove in-memory Map.

CQ-ORCH-3: Redis KEYS Command in Production [CRITICAL]

• File: apps/orchestrator/src/valkey/valkey.client.ts:116, 187
• Issue: KEYS is O(N) and blocks entire Redis instance.
• Fix: Use SCAN for non-blocking iteration.

CQ-ORCH-4: No Timeout Cleanup for AbortController [HIGH]

• File: apps/orchestrator/src/coordinator/coordinator-client.service.ts:67-81, 156-166
• Issue: clearTimeout only called on success path, not in catch block. Timer leak per retry.
• Fix: Use try-finally to guarantee cleanup.

CQ-ORCH-5: TOCTOU Race in State Transitions [HIGH]

• File: apps/orchestrator/src/spawner/agent-lifecycle.service.ts:31-53
• Issue: Read state, validate, then write is not atomic. Concurrent transitions can overwrite each other.
• Fix: Use Valkey Lua script for atomic check-and-set.

CQ-ORCH-6: N+1 Query in listTasks/listAgents [CRITICAL]

• File: apps/orchestrator/src/valkey/valkey.client.ts:114-127, 185-198
• Issue: 1 + N queries (one KEYS + one GET per key). 1000 tasks = 1001 round trips.
• Fix: Use MGET for batch retrieval after SCAN. 100-500x faster.

CQ-ORCH-7: Docker Force Remove Loses Data [MEDIUM]

• File: apps/orchestrator/src/spawner/docker-sandbox.service.ts:179
• Issue: force: true always used, bypassing graceful shutdown. Work-in-progress lost.
• Fix: Stop before remove. Only force as last resort.

CQ-ORCH-8: KillAllAgents Doesn't Distinguish Error Types [MEDIUM]

• File: apps/orchestrator/src/killswitch/killswitch.service.ts:125-137
• Issue: "Already terminated" counted same as "cleanup failed." Misleading metrics.
• Fix: Add "skipped" category for expected state transition failures.

CQ-ORCH-9: Duplicate Validation Logic [CODE SMELL]

• Files: agent-spawner.service.ts:98-119, agents.controller.ts:192-213
• Issue: Both implement identical spawn request validation.
• Fix: Remove from controller. Rely on DTOs + ValidationPipe.

CQ-ORCH-10: BullMQ Job Retention May Cause Memory Growth [LOW]

• File: apps/orchestrator/src/queue/queue.service.ts:52-60
• Issue: Retention of 1000 failed jobs for 24 hours may be excessive under load.
• Fix: Make configurable via environment variables.

---

Remediation Priority Matrix

Priority	ID	Title	Effort
P0	CQ-API-6	Hardcoded OIDC values	30min
P0	CQ-ORCH-3	KEYS -> SCAN	1hr
P0	CQ-ORCH-6	N+1 queries -> MGET	1hr
P0	CQ-WEB-5	Boolean logic bug (?? -> ||)	5min
P1	CQ-ORCH-1	Session Map cleanup	1hr
P1	CQ-API-1	WebSocket timer leak	30min
P1	CQ-API-2	Runner jobs interval leak	30min
P1	CQ-WEB-1	useWebSocket stale closure	1hr
P1	CQ-WEB-4	useChat stale messages	1hr
P1	CQ-ORCH-5	Atomic state transitions	2hr
P2	CQ-WEB-7	Kanban optimistic rollback	1hr
P2	CQ-ORCH-2	Single source of truth	2hr
P2	CQ-ORCH-4	AbortController cleanup	30min
P2	CQ-API-4	Redis listener cleanup	30min
P3	CQ-WEB-8	React.memo adoption	2hr
P3	CQ-WEB-11	Accessibility labels	1hr
P3	Remaining	Lower priority items	3hr

Estimated total remediation effort: 2-3 days