feat(ai-context): Phase A.4 — context-aware AI messages with LLM fallback

Add AI-enriched context message generation:

- backend/src/lib/ai-context.ts: LLM-powered context generator with keyword fallback
  - Calls extraction-service timer-context task when EXTRACTION_SERVICE_URL is set
  - Falls back to keyword rules, then generic message
  - Gated behind isFeatureEnabled('ai_context_messages.enabled')
- backend/src/lib/config.ts: Add EXTRACTION_SERVICE_URL env var
- backend/src/server.ts: POST /api/context-message route
- web/src/lib/context-messages.ts: fetchEnrichedMessage() with graceful degradation
- Updated AGENTIC_AI_ROADMAP.md checkboxes for Phase A.1 + A.2

All 219 backend tests + 394 web tests pass. No breaking changes.

backend/src/lib/ai-context.ts

@@ -0,0 +1,132 @@
+/**
+ * AI-powered context message generator (Phase A.4).
+ *
+ * Accepts timer metadata + user context. Returns an enriched prep message.
+ * Falls back to keyword rules if LLM is unavailable or the feature flag is off.
+ *
+ * Gate: isFeatureEnabled('ai_context_messages.enabled')
+ */
+
+import { isFeatureEnabled } from './feature-flags.js';
+import { config } from './config.js';
+
+// ── Keyword fallback (same rules as web/src/lib/context-messages.ts) ──
+
+interface ContextRule {
+  keywords: string[];
+  messages: string[];
+}
+
+const CONTEXT_RULES: ContextRule[] = [
+  { keywords: ['meeting', 'standup', 'sync', 'huddle', 'scrum', '1:1'], messages: ['Review your agenda'] },
+  { keywords: ['call', 'phone', 'dial'], messages: ['Have the number ready'] },
+  { keywords: ['presentation', 'demo', 'pitch'], messages: ['Run through your slides'] },
+  { keywords: ['flight', 'plane', 'airport'], messages: ['Check in online'] },
+  { keywords: ['doctor', 'dentist', 'appointment', 'clinic'], messages: ['Bring your insurance card'] },
+  { keywords: ['workout', 'exercise', 'gym', 'run', 'yoga'], messages: ['Hydrate beforehand'] },
+  { keywords: ['deadline', 'due', 'submit'], messages: ['Final review before submitting'] },
+  { keywords: ['focus', 'deep work'], messages: ['Close unnecessary tabs'] },
+  { keywords: ['cook', 'bake', 'recipe'], messages: ['Gather your ingredients'] },
+  { keywords: ['sleep', 'bed', 'bedtime'], messages: ['Start winding down'] },
+];
+
+function keywordFallback(label: string): string | null {
+  const lower = label.toLowerCase();
+  for (const rule of CONTEXT_RULES) {
+    if (rule.keywords.some(kw => lower.includes(kw))) {
+      return rule.messages[0];
+    }
+  }
+  return null;
+}
+
+// ── Input / Output types ──
+
+export interface ContextMessageInput {
+  timerLabel: string;
+  category?: string;
+  urgency?: string;
+  minutesBefore: number;
+  timeOfDay?: string;
+  recentTimerLabels?: string[];
+}
+
+export interface ContextMessageResult {
+  message: string;
+  source: 'llm' | 'keyword' | 'generic';
+}
+
+// ── LLM enrichment (extraction-service or ollama-client) ──
+
+// TODO(AGENTIC-6): Replace this stub with a real LLM call via
+// @bytelyst/extraction client (timer-context task) or @bytelyst/ollama-client.
+// For now we build the prompt and return a simulated enriched message.
+async function llmEnrich(input: ContextMessageInput): Promise<string | null> {
+  // Only attempt if extraction service URL is configured
+  const extractionUrl = config.EXTRACTION_SERVICE_URL;
+  if (!extractionUrl) return null;
+
+  try {
+    const prompt = buildPrompt(input);
+    const res = await fetch(`${extractionUrl}/api/extract`, {
+      method: 'POST',
+      headers: { 'Content-Type': 'application/json' },
+      body: JSON.stringify({
+        task: 'timer-context',
+        input: prompt,
+        options: { maxTokens: 100 },
+      }),
+      signal: AbortSignal.timeout(5_000),
+    });
+
+    if (!res.ok) return null;
+
+    const data = await res.json() as { result?: string };
+    return data.result ?? null;
+  } catch {
+    return null;
+  }
+}
+
+function buildPrompt(input: ContextMessageInput): string {
+  const parts = [
+    `Timer: "${input.timerLabel}" fires in ${input.minutesBefore} minutes.`,
+  ];
+  if (input.category) parts.push(`Category: ${input.category}.`);
+  if (input.urgency) parts.push(`Urgency: ${input.urgency}.`);
+  if (input.timeOfDay) parts.push(`Time of day: ${input.timeOfDay}.`);
+  if (input.recentTimerLabels?.length) {
+    parts.push(`Recent timers: ${input.recentTimerLabels.slice(0, 5).join(', ')}.`);
+  }
+  parts.push('Give a short, actionable prep suggestion (1-2 sentences max).');
+  return parts.join(' ');
+}
+
+// ── Main function ──
+
+export async function generateContextMessage(
+  input: ContextMessageInput
+): Promise<ContextMessageResult> {
+  // 1. Try LLM enrichment if feature flag is on
+  if (isFeatureEnabled('ai_context_messages.enabled')) {
+    const llmMessage = await llmEnrich(input);
+    if (llmMessage) {
+      return { message: llmMessage, source: 'llm' };
+    }
+  }
+
+  // 2. Fall back to keyword rules
+  const keywordMessage = keywordFallback(input.timerLabel);
+  if (keywordMessage) {
+    return { message: keywordMessage, source: 'keyword' };
+  }
+
+  // 3. Generic fallback
+  const minutesStr = input.minutesBefore >= 60
+    ? `${Math.floor(input.minutesBefore / 60)}h ${input.minutesBefore % 60}m`
+    : `${input.minutesBefore}m`;
+  return {
+    message: `${input.timerLabel} is coming up in ${minutesStr.trim()} — get ready!`,
+    source: 'generic',
+  };
+}

backend/src/lib/config.ts

@@ -14,6 +14,7 @@ const envSchema = baseBackendConfigSchema.extend({
   FIELD_ENCRYPT_KEY: z.string().optional(),
   FIELD_ENCRYPT_MEK_NAME: z.string().default('chronomind-mek'),
   AZURE_KEYVAULT_URL: z.string().optional(),
+  EXTRACTION_SERVICE_URL: z.string().optional(),
 });
 
 export const config = envSchema.parse(process.env);

backend/src/server.ts

@@ -18,6 +18,7 @@ import { initDatastore } from './lib/datastore.js';
 import { initEncryption } from './lib/field-encrypt.js';
 import { config } from './lib/config.js';
 import { getAllFlags } from './lib/feature-flags.js';
+import { generateContextMessage } from './lib/ai-context.js';
 import { getBufferedEvents, flushEvents } from './lib/telemetry.js';
 import { PRODUCT_ID, productConfig } from './lib/product-config.js';
 
@@ -56,6 +57,22 @@ await app.register(sharedTimerRoutes, { prefix: '/api' });
 await app.register(webhookRoutes, { prefix: '/api' });
 await app.register(agentActionRoutes, { prefix: '/api' });
 
+// ── Phase A.4: Context-aware AI messages ─────────────────────────
+app.post('/api/context-message', async req => {
+  const body = req.body as {
+    timerLabel: string;
+    category?: string;
+    urgency?: string;
+    minutesBefore: number;
+    timeOfDay?: string;
+    recentTimerLabels?: string[];
+  };
+  if (!body.timerLabel || typeof body.minutesBefore !== 'number') {
+    return { message: 'Get ready!', source: 'generic' as const };
+  }
+  return generateContextMessage(body);
+});
+
 // ── Bootstrap (no auth) ──────────────────────────────────────────
 app.get('/api/bootstrap', async () => ({
   productId: productConfig.productId,

docs/AGENTIC_AI_ROADMAP.md

@@ -162,32 +162,33 @@ These proxy to `chronomind-backend` (port 4011) via `chronomind-client.ts`.
 
 Add 4 new endpoint groups to the product backend. These are plain REST routes — NOT MCP tools:
 
-- [ ] `backend/src/modules/timers/routes.ts` — add reschedule + availability endpoints (commit: )
+- [x] `backend/src/modules/timers/routes.ts` — add reschedule + availability endpoints (commit: 686f5fb)
   - `POST /api/timers/:id/reschedule` — shift timer by delta or to new time
   - `GET /api/timers/availability?start=<ISO>&end=<ISO>&minSlotMinutes=<N>` — find free slots
   - Gate behind `isFeatureEnabled('mcp.enabled')` flag
-- [ ] `backend/src/modules/routines/routes.ts` — add start-routine endpoint (commit: )
+- [x] `backend/src/modules/routines/routes.ts` — add start-routine endpoint (commit: 686f5fb)
   - `POST /api/routines/:id/start` — start a routine template (changes status → running)
   - Gate behind `isFeatureEnabled('mcp.enabled')` flag
-- [ ] Tests for new timer + routine endpoints (commit: )
+- [x] Tests for new timer + routine endpoints (commit: 29a4802)
 
 ### A.2 — Agent Action Audit Trail (New Backend Module)
 
-- [ ] `backend/src/modules/agent-actions/types.ts` — Zod schemas (commit: )
+- [x] `backend/src/modules/agent-actions/types.ts` — Zod schemas (commit: 29a4802)
   - Fields: `id`, `userId`, `productId`, `actorId`, `actorType` (agent/user/mcp), `toolName`, `actionType`, `state` (proposed/approved/applied/rejected), `reason`, `payload`, `createdAt`
   - Every Cosmos doc includes `productId: "chronomind"`
-- [ ] `backend/src/modules/agent-actions/repository.ts` — CRUD (commit: )
+- [x] `backend/src/modules/agent-actions/repository.ts` — CRUD (commit: 29a4802)
   - Container: `cm_agent_actions`, partition: `/userId`
   - Uses `@bytelyst/datastore` `getCollection()` — never direct Cosmos SDK
-- [ ] `backend/src/modules/agent-actions/routes.ts` — REST endpoints (commit: )
+- [x] `backend/src/modules/agent-actions/routes.ts` — REST endpoints (commit: 29a4802)
   - `GET /api/agent-actions` — list (filterable by state, actorId, toolName)
+  - `POST /api/agent-actions` — create action (used by MCP tools)
   - `POST /api/agent-actions/:id/approve` — approve proposed action
   - `POST /api/agent-actions/:id/reject` — reject proposed action
   - `POST /api/agent-actions/batch-approve` — batch approve by actorId
   - Gate behind `isFeatureEnabled('agent_inbox.enabled')` flag
-- [ ] Register `agentActionRoutes` in `server.ts` (commit: )
-- [ ] Register `cm_agent_actions` container in `cosmos-init.ts` (commit: )
-- [ ] Agent action tests (commit: )
+- [x] Register `agentActionRoutes` in `server.ts` (commit: 29a4802)
+- [x] Register `cm_agent_actions` container in `cosmos-init.ts` (commit: 29a4802)
+- [x] Agent action tests — 22 tests (commit: 29a4802)
 
 ### A.3 — Extend Centralized MCP Server (common-plat)
 

web/src/lib/context-messages.ts

@@ -169,3 +169,50 @@ export function hasContextMatch(label: string): boolean {
 export function getContextRules(): ContextRule[] {
   return [...CONTEXT_RULES];
 }
+
+// ── Phase A.4: AI-enriched context messages ─────────────────────
+
+export interface EnrichedMessageResult {
+  message: string;
+  source: 'llm' | 'keyword' | 'generic';
+}
+
+/**
+ * Fetch an AI-enriched context message from the backend.
+ * Falls back to local keyword rules if the backend is unreachable.
+ *
+ * Graceful degradation: keyword rules remain primary, LLM messages
+ * shown as "AI suggestion" in the UI.
+ */
+export async function fetchEnrichedMessage(params: {
+  timerLabel: string;
+  category?: string;
+  urgency?: string;
+  minutesBefore: number;
+  timeOfDay?: string;
+  recentTimerLabels?: string[];
+}): Promise<EnrichedMessageResult> {
+  // TODO(AGENTIC-7): Use the backend URL from product-config or auth-api
+  // instead of relative path, once backend is always available.
+  try {
+    const backendUrl = process.env.NEXT_PUBLIC_CHRONOMIND_BACKEND_URL ?? 'http://localhost:4011';
+    const res = await fetch(`${backendUrl}/api/context-message`, {
+      method: 'POST',
+      headers: { 'Content-Type': 'application/json' },
+      body: JSON.stringify(params),
+      signal: AbortSignal.timeout(3_000),
+    });
+    if (res.ok) {
+      return await res.json() as EnrichedMessageResult;
+    }
+  } catch {
+    // Fall through to local fallback
+  }
+
+  // Local fallback — keyword rules
+  const keywordMsg = getContextMessage(params.timerLabel);
+  if (keywordMsg) {
+    return { message: keywordMsg, source: 'keyword' };
+  }
+  return { message: `${params.timerLabel} is coming up — get ready!`, source: 'generic' };
+}