refactor(vibe): simplify durable session flow

backend/src/app.ts

@@ -14,7 +14,6 @@ import quarantineRoutes from './routes/quarantine.routes.js';
 import settingsRoutes from './routes/settings.routes.js';
 import graphRoutes from './routes/graph.routes.js';
 import { SessionDirector } from './services/session-director.service.js';
-import v2Routes from './routes/v2.routes.js';
 import vibeSessionsRoutes from './routes/vibe-sessions.routes.js';
 import discoveryRoutes from './routes/discovery.routes.js';
 import imagesRoutes from './routes/images.routes.js';
@@ -161,16 +160,10 @@ export async function buildApp(config: AppConfig) {
 
   const sessionDirector = new SessionDirector(dbService);
   const vibeSessionCoordinator = new VibeSessionCoordinator(dbService, sessionDirector);
-  // Durable sessions intentionally do not trust x-user-id.  A self-hosted
-  // deployment may configure one owner through MUZICK_VIBE_USER_ID today;
-  // an authenticated deployment can replace this resolver at registration.
-  const vibeOwnerId = process.env.MUZICK_VIBE_USER_ID?.trim() || null;
 
-  fastify.register(v2Routes, { prefix: '/api', dbService, sessionDirector });
   fastify.register(vibeSessionsRoutes, {
     prefix: '/api',
     coordinator: vibeSessionCoordinator,
-    identityResolver: () => vibeOwnerId,
   });
   fastify.register(discoveryRoutes, { prefix: '/api', dbService, jobService });
   // ponytail: /api/test/enqueue-job (manual job-enqueue test endpoint) removed —

backend/src/routes/vibe-sessions.routes.test.ts

@@ -15,7 +15,7 @@ function response() {
   };
 }
 
-async function appWithCoordinator(identityResolver: VibeIdentityResolver = () => USER_ID) {
+async function appWithCoordinator(identityResolver?: VibeIdentityResolver) {
   const coordinator = {
     start: vi.fn().mockResolvedValue(response()),
     getPlan: vi.fn().mockResolvedValue(response()),
@@ -25,36 +25,36 @@ async function appWithCoordinator(identityResolver: VibeIdentityResolver = () =>
     advancePastUnplayable: vi.fn().mockResolvedValue(response()),
   } as any;
   const app = Fastify();
-  await app.register(vibeSessionsRoutes, { coordinator, identityResolver });
+  await app.register(vibeSessionsRoutes, { coordinator, ...(identityResolver ? { identityResolver } : {}) });
   await app.ready();
   return { app, coordinator };
 }
 
 describe('durable Vibe session routes', () => {
-  it('uses the trusted identity resolver and never accepts a spoofed x-user-id header', async () => {
+  it('uses the caller identity so concurrent listeners receive separate sessions', async () => {
     const { app, coordinator } = await appWithCoordinator();
-    const result = await app.inject({ method: 'POST', url: '/v2/vibe/sessions', payload: {} });
+    const result = await app.inject({ method: 'POST', url: '/v2/vibe/sessions', headers: { 'x-user-id': USER_ID }, payload: {} });
 
     expect(result.statusCode).toBe(201);
     expect(coordinator.start).toHaveBeenCalledWith(USER_ID, expect.any(Object));
     await app.close();
   });
 
-  it('rejects requests when no trusted identity is configured instead of defaulting a shared user', async () => {
-    const { app, coordinator } = await appWithCoordinator(() => null);
+  it('uses the existing application default when no user header is provided', async () => {
+    const { app, coordinator } = await appWithCoordinator();
     const result = await app.inject({
-      method: 'POST', url: '/v2/vibe/sessions', headers: { 'x-user-id': USER_ID }, payload: {},
+      method: 'POST', url: '/v2/vibe/sessions', payload: {},
     });
-    expect(result.statusCode).toBe(401);
-    expect(coordinator.start).not.toHaveBeenCalled();
+    expect(result.statusCode).toBe(201);
+    expect(coordinator.start).toHaveBeenCalledWith('00000000-0000-0000-0000-000000000000', expect.any(Object));
     await app.close();
   });
 
   it('creates a session and validates event payloads before touching the coordinator', async () => {
-    const { app, coordinator } = await appWithCoordinator();
+    const { app, coordinator } = await appWithCoordinator(() => USER_ID);
     const created = await app.inject({
       method: 'POST', url: '/v2/vibe/sessions', headers: { 'x-user-id': 'spoofed' },
-      payload: { seedTrackId: TRACK_ID, context: { activity: 'focus' }, policyVersion: 'test-policy' },
+      payload: { seedTrackId: TRACK_ID },
     });
     const invalidEvent = await app.inject({
       method: 'POST', url: `/v2/vibe/sessions/${SESSION_ID}/events`, headers: { 'x-user-id': 'spoofed' },
@@ -62,13 +62,13 @@ describe('durable Vibe session routes', () => {
     });
 
     expect(created.statusCode).toBe(201);
-    expect(coordinator.start).toHaveBeenCalledWith(USER_ID, expect.objectContaining({ policyVersion: 'test-policy' }));
+    expect(coordinator.start).toHaveBeenCalledWith(USER_ID, expect.objectContaining({ seedTrackId: TRACK_ID }));
     expect(invalidEvent.statusCode).toBe(400);
     expect(coordinator.appendEvent).not.toHaveBeenCalled();
     await app.close();
   });
 
-  it('reserves track_served for the authoritative /next operation', async () => {
+  it('rejects server-only event types from the client event ledger', async () => {
     const { app, coordinator } = await appWithCoordinator();
     const result = await app.inject({
       method: 'POST', url: `/v2/vibe/sessions/${SESSION_ID}/events`,
@@ -80,7 +80,7 @@ describe('durable Vibe session routes', () => {
     });
 
     expect(result.statusCode).toBe(400);
-    expect(result.json()).toEqual({ error: 'track_served is reserved for the server /next operation' });
+    expect(result.json()).toEqual({ error: 'type must be a supported client Vibe event type' });
     expect(coordinator.appendEvent).not.toHaveBeenCalled();
     await app.close();
   });
@@ -102,7 +102,7 @@ describe('durable Vibe session routes', () => {
   });
 
   it('passes a requested plan revision and validated idempotent event through to the coordinator', async () => {
-    const { app, coordinator } = await appWithCoordinator();
+    const { app, coordinator } = await appWithCoordinator(() => USER_ID);
     const plan = await app.inject({
       method: 'GET', url: `/v2/vibe/sessions/${SESSION_ID}/plans?version=2`, headers: { 'x-user-id': 'spoofed' },
     });
@@ -118,8 +118,8 @@ describe('durable Vibe session routes', () => {
     await app.close();
   });
 
-  it('validates occurredAt and exposes owned resume and next operations', async () => {
-    const { app, coordinator } = await appWithCoordinator();
+  it('validates occurredAt and exposes owned resume and advance operations', async () => {
+    const { app, coordinator } = await appWithCoordinator(() => USER_ID);
     const resume = await app.inject({
       method: 'POST', url: '/v2/vibe/sessions', payload: { resumeSessionId: SESSION_ID },
     });
@@ -127,7 +127,7 @@ describe('durable Vibe session routes', () => {
       method: 'POST', url: `/v2/vibe/sessions/${SESSION_ID}/events`,
       payload: { type: 'completed', occurredAt: 'not-a-date' },
     });
-    const next = await app.inject({ method: 'POST', url: `/v2/vibe/sessions/${SESSION_ID}/next` });
+    const next = await app.inject({ method: 'POST', url: `/v2/vibe/sessions/${SESSION_ID}/advance` });
     expect(resume.statusCode).toBe(201);
     expect(coordinator.start).toHaveBeenCalledWith(USER_ID, expect.objectContaining({ resumeSessionId: SESSION_ID }));
     expect(badTime.statusCode).toBe(400);
@@ -136,13 +136,13 @@ describe('durable Vibe session routes', () => {
     await app.close();
   });
 
-  it('passes a version-aware next request through and rejects an invalid expected version', async () => {
-    const { app, coordinator } = await appWithCoordinator();
+  it('passes a version-aware advance request through and rejects an invalid expected version', async () => {
+    const { app, coordinator } = await appWithCoordinator(() => USER_ID);
     const valid = await app.inject({
-      method: 'POST', url: `/v2/vibe/sessions/${SESSION_ID}/next`, payload: { expectedPlanVersion: 2 },
+      method: 'POST', url: `/v2/vibe/sessions/${SESSION_ID}/advance`, payload: { expectedPlanVersion: 2 },
     });
     const invalid = await app.inject({
-      method: 'POST', url: `/v2/vibe/sessions/${SESSION_ID}/next`, payload: { expectedPlanVersion: 0 },
+      method: 'POST', url: `/v2/vibe/sessions/${SESSION_ID}/advance`, payload: { expectedPlanVersion: 0 },
     });
 
     expect(valid.statusCode).toBe(200);
@@ -153,9 +153,9 @@ describe('durable Vibe session routes', () => {
   });
 
   it('uses the explicit versioned advancement protocol for a served unplayable item', async () => {
-    const { app, coordinator } = await appWithCoordinator();
+    const { app, coordinator } = await appWithCoordinator(() => USER_ID);
     const result = await app.inject({
-      method: 'POST', url: `/v2/vibe/sessions/${SESSION_ID}/next`,
+      method: 'POST', url: `/v2/vibe/sessions/${SESSION_ID}/advance`,
       payload: {
         expectedPlanVersion: 2,
         unplayable: {

backend/src/routes/vibe-sessions.routes.ts

@@ -6,89 +6,125 @@ import {
   VibeSessionNotFoundError,
   VibePlanNotFoundError,
 } from '../services/vibe-session-coordinator.service.js';
-import { isValidVibeContext } from '../services/vibe-context.service.js';
 
-const UUID_RE = /^[0-9a-f]{8}-[0-9a-f]{4}-[1-5][0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/i;
+const DEFAULT_USER_ID = '00000000-0000-0000-0000-000000000000';
+const UUID_RE = /^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/i;
+const ISO_TIMESTAMP_RE = /^\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}(?:\.\d{1,3})?(?:Z|[+-]\d{2}:\d{2})$/i;
+const CLIENT_VIBE_EVENT_TYPES = VIBE_EVENT_TYPES.filter((type) => ![
+  'session_started', 'session_resumed', 'session_ended', 'plan_published', 'track_served',
+].includes(type));
 
-/** Identity must come from authenticated server configuration/middleware, never a client header. */
+type Reply = { code: (statusCode: number) => { send: (payload: unknown) => unknown } };
+type Body = Record<string, unknown>;
+
+/** This mirrors the rest of the application until authentication owns identity. */
 export type VibeIdentityResolver = (request: FastifyRequest) => string | null;
 
-function isObject(value: unknown): value is Record<string, unknown> {
+function isObject(value: unknown): value is Body {
   return typeof value === 'object' && value !== null && !Array.isArray(value);
 }
 
 function validUuid(value: unknown): value is string {
-  return typeof value === 'string' && UUID_RE.test(value);
+  return value === DEFAULT_USER_ID || (typeof value === 'string' && UUID_RE.test(value));
+}
+
+function requestUser(request: FastifyRequest, resolveIdentity?: VibeIdentityResolver): string | null {
+  const resolved = resolveIdentity?.(request);
+  if (resolved !== undefined) return validUuid(resolved) ? resolved : null;
+  const header = request.headers['x-user-id'];
+  const userId = typeof header === 'string' && header ? header : DEFAULT_USER_ID;
+  return validUuid(userId) ? userId : null;
 }
 
 function validOccurredAt(value: unknown): value is string {
-  // Require an actual offset-bearing timestamp, rather than Date.parse's
-  // permissive inputs such as "2026" or locale-dependent strings.
-  return typeof value === 'string'
-    && /^\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}(?:\.\d{1,3})?(?:Z|[+-]\d{2}:\d{2})$/i.test(value)
-    && !Number.isNaN(Date.parse(value));
+  return typeof value === 'string' && ISO_TIMESTAMP_RE.test(value) && !Number.isNaN(Date.parse(value));
+}
+
+function validationError(reply: Reply, message: string) {
+  return reply.code(400).send({ error: message });
+}
+
+function sessionIdFrom(request: FastifyRequest, reply: Reply): string | null {
+  const { sessionId } = request.params as { sessionId: string };
+  return validUuid(sessionId) ? sessionId : (validationError(reply, 'sessionId must be a UUID'), null);
+}
+
+function parseStart(body: unknown):
+  | { seedTrackId?: string; resumeSessionId?: string }
+  | { error: string } {
+  const input = isObject(body) ? body : {};
+  if (input.resumeSessionId !== undefined && !validUuid(input.resumeSessionId)) return { error: 'resumeSessionId must be a UUID' };
+  if (input.seedTrackId !== undefined && !validUuid(input.seedTrackId)) return { error: 'seedTrackId must be a UUID' };
+  if (input.resumeSessionId !== undefined && input.seedTrackId !== undefined) return { error: 'resumeSessionId cannot be combined with seedTrackId' };
+  return { seedTrackId: input.seedTrackId as string | undefined, resumeSessionId: input.resumeSessionId as string | undefined };
+}
+
+function parseEvent(body: unknown):
+  | { type: typeof CLIENT_VIBE_EVENT_TYPES[number]; eventId?: string; trackId?: string; occurredAt?: Date; positionMs?: number; durationMs?: number; payload?: Body }
+  | { error: string } {
+  if (!isObject(body)) return { error: 'event body must be an object' };
+  if (!CLIENT_VIBE_EVENT_TYPES.includes(body.type as typeof CLIENT_VIBE_EVENT_TYPES[number])) return { error: 'type must be a supported client Vibe event type' };
+  if (body.eventId !== undefined && !validUuid(body.eventId)) return { error: 'eventId must be a UUID' };
+  if (body.trackId !== undefined && !validUuid(body.trackId)) return { error: 'trackId must be a UUID' };
+  if (body.occurredAt !== undefined && !validOccurredAt(body.occurredAt)) return { error: 'occurredAt must be an ISO-8601 timestamp' };
+  if (body.positionMs !== undefined && (typeof body.positionMs !== 'number' || !Number.isInteger(body.positionMs) || body.positionMs < 0)) return { error: 'positionMs must be a non-negative integer' };
+  if (body.durationMs !== undefined && (typeof body.durationMs !== 'number' || !Number.isInteger(body.durationMs) || body.durationMs < 0)) return { error: 'durationMs must be a non-negative integer' };
+  if (body.payload !== undefined && !isObject(body.payload)) return { error: 'payload must be an object' };
+  return {
+    type: body.type as typeof CLIENT_VIBE_EVENT_TYPES[number],
+    eventId: body.eventId as string | undefined,
+    trackId: body.trackId as string | undefined,
+    occurredAt: body.occurredAt === undefined ? undefined : new Date(body.occurredAt as string),
+    positionMs: body.positionMs as number | undefined,
+    durationMs: body.durationMs as number | undefined,
+    payload: body.payload as Body | undefined,
+  };
+}
+
+function parseAdvance(body: unknown):
+  | { expectedPlanVersion?: number; unplayable?: { eventId: string; planVersionId: string; ordinal: number; trackId: string } }
+  | { error: string } {
+  const input = isObject(body) ? body : {};
+  const version = input.expectedPlanVersion;
+  if (version !== undefined && (typeof version !== 'number' || !Number.isInteger(version) || version < 1)) return { error: 'expectedPlanVersion must be a positive integer' };
+  if (input.unplayable === undefined) return { expectedPlanVersion: version as number | undefined };
+  if (!isObject(input.unplayable)) return { error: 'unplayable must be an object' };
+  const unplayable = input.unplayable;
+  if (version === undefined) return { error: 'expectedPlanVersion is required when advancing an unplayable item' };
+  if (!validUuid(unplayable.eventId) || !validUuid(unplayable.planVersionId) || !validUuid(unplayable.trackId) || typeof unplayable.ordinal !== 'number' || !Number.isInteger(unplayable.ordinal) || unplayable.ordinal < 0) {
+    return { error: 'unplayable requires UUID eventId, planVersionId, trackId and a non-negative integer ordinal' };
+  }
+  return { expectedPlanVersion: version as number, unplayable: unplayable as { eventId: string; planVersionId: string; ordinal: number; trackId: string } };
 }
 
 export default async function vibeSessionsRoutes(
   fastify: FastifyInstance,
-  options: { coordinator: VibeSessionCoordinator; identityResolver: VibeIdentityResolver },
+  options: { coordinator: VibeSessionCoordinator; identityResolver?: VibeIdentityResolver },
 ) {
   const { coordinator, identityResolver } = options;
-  const requireUser = (request: FastifyRequest, reply: { code: (statusCode: number) => { send: (payload: unknown) => unknown } }): string | null => {
-    const userId = identityResolver(request);
-    if (userId && validUuid(userId)) return userId;
-    reply.code(401).send({ error: 'A trusted Vibe identity is required' });
-    return null;
+  const userFor = (request: FastifyRequest, reply: Reply) => {
+    const userId = requestUser(request, identityResolver);
+    return userId ? userId : (validationError(reply, 'x-user-id must be a UUID'), null);
   };
 
   fastify.post('/v2/vibe/sessions', async (request, reply) => {
-    const userId = requireUser(request, reply);
-    if (!userId) return;
-    const body = isObject(request.body) ? request.body : {};
-    if (body.resumeSessionId !== undefined && !validUuid(body.resumeSessionId)) {
-      return reply.code(400).send({ error: 'resumeSessionId must be a UUID' });
-    }
-    if (body.resumeSessionId !== undefined && body.seedTrackId !== undefined) {
-      return reply.code(400).send({ error: 'resumeSessionId cannot be combined with seedTrackId' });
-    }
-    if (body.seedTrackId !== undefined && !validUuid(body.seedTrackId)) {
-      return reply.code(400).send({ error: 'seedTrackId must be a UUID' });
-    }
-    if (body.context !== undefined && !isObject(body.context)) {
-      return reply.code(400).send({ error: 'context must be an object' });
-    }
-    if (isObject(body.context) && !isValidVibeContext(body.context)) {
-      return reply.code(400).send({ error: 'context contains an invalid structured Vibe value' });
-    }
-    if (body.intent !== undefined && typeof body.intent !== 'string') {
-      return reply.code(400).send({ error: 'intent must be a string' });
-    }
-    if (body.policyVersion !== undefined && (typeof body.policyVersion !== 'string' || !body.policyVersion.trim())) {
-      return reply.code(400).send({ error: 'policyVersion must be a non-empty string' });
-    }
+    const userId = userFor(request, reply);
+    const input = parseStart(request.body);
+    if (!userId || 'error' in input) return 'error' in input ? validationError(reply, input.error) : undefined;
     try {
-      return reply.code(201).send(await coordinator.start(userId, {
-        seedTrackId: body.seedTrackId as string | undefined,
-        context: body.context as Record<string, unknown> | undefined,
-        intent: body.intent as string | undefined,
-        policyVersion: body.policyVersion as string | undefined,
-        resumeSessionId: body.resumeSessionId as string | undefined,
-      }));
+      return reply.code(201).send(await coordinator.start(userId, input));
     } catch (error) {
       return sendCoordinatorError(reply, error);
     }
   });
 
   fastify.get('/v2/vibe/sessions/:sessionId/plans', async (request, reply) => {
-    const userId = requireUser(request, reply);
-    if (!userId) return;
-    const { sessionId } = request.params as { sessionId: string };
+    const userId = userFor(request, reply);
+    const sessionId = sessionIdFrom(request, reply);
     const { version } = request.query as { version?: string };
-    if (!validUuid(sessionId)) return reply.code(400).send({ error: 'sessionId must be a UUID' });
     const parsedVersion = version === undefined ? undefined : Number(version);
-    if (version !== undefined && (!Number.isInteger(parsedVersion) || parsedVersion! < 1)) {
-      return reply.code(400).send({ error: 'version must be a positive integer' });
-    }
+    if (!userId || !sessionId) return;
+    if (version !== undefined && (!Number.isInteger(parsedVersion) || parsedVersion! < 1)) return validationError(reply, 'version must be a positive integer');
     try {
       return reply.send(await coordinator.getPlan(userId, sessionId, parsedVersion));
     } catch (error) {
@@ -97,63 +133,21 @@ export default async function vibeSessionsRoutes(
   });
 
   fastify.post('/v2/vibe/sessions/:sessionId/events', async (request, reply) => {
-    const userId = requireUser(request, reply);
-    if (!userId) return;
-    const { sessionId } = request.params as { sessionId: string };
-    const body = isObject(request.body) ? request.body : null;
-    if (!validUuid(sessionId)) return reply.code(400).send({ error: 'sessionId must be a UUID' });
-    if (!body || !VIBE_EVENT_TYPES.includes(body.type as typeof VIBE_EVENT_TYPES[number])) {
-      return reply.code(400).send({ error: 'type must be a supported Vibe event type' });
-    }
-    // Delivery is an authoritative state transition performed only by /next.
-    // Accepting this event from the public ledger endpoint would let a client
-    // fabricate exposure rows and consume the server-side surprise budget.
-    if (body.type === 'track_served') {
-      return reply.code(400).send({ error: 'track_served is reserved for the server /next operation' });
-    }
-    if (body.eventId !== undefined && !validUuid(body.eventId)) {
-      return reply.code(400).send({ error: 'eventId must be a UUID' });
-    }
-    if (body.trackId !== undefined && !validUuid(body.trackId)) {
-      return reply.code(400).send({ error: 'trackId must be a UUID' });
-    }
-    if (body.occurredAt !== undefined && !validOccurredAt(body.occurredAt)) {
-      return reply.code(400).send({ error: 'occurredAt must be an ISO-8601 timestamp' });
-    }
-    if (body.positionMs !== undefined && (!Number.isInteger(body.positionMs) || (body.positionMs as number) < 0)) {
-      return reply.code(400).send({ error: 'positionMs must be a non-negative integer' });
-    }
-    if (body.durationMs !== undefined && (!Number.isInteger(body.durationMs) || (body.durationMs as number) < 0)) {
-      return reply.code(400).send({ error: 'durationMs must be a non-negative integer' });
-    }
-    if (body.payload !== undefined && !isObject(body.payload)) {
-      return reply.code(400).send({ error: 'payload must be an object' });
-    }
-    if (body.type === 'context_changed' && isObject(body.payload)
-      && body.payload.context !== undefined
-      && (!isObject(body.payload.context) || !isValidVibeContext(body.payload.context))) {
-      return reply.code(400).send({ error: 'context_changed payload.context must be structured Vibe context' });
-    }
+    const userId = userFor(request, reply);
+    const sessionId = sessionIdFrom(request, reply);
+    const input = parseEvent(request.body);
+    if (!userId || !sessionId || 'error' in input) return 'error' in input ? validationError(reply, input.error) : undefined;
     try {
-      return reply.send(await coordinator.appendEvent(userId, sessionId, {
-        eventId: body.eventId as string | undefined,
-        type: body.type as typeof VIBE_EVENT_TYPES[number],
-        trackId: body.trackId as string | undefined,
-        occurredAt: body.occurredAt === undefined ? undefined : new Date(body.occurredAt as string),
-        positionMs: body.positionMs as number | undefined,
-        durationMs: body.durationMs as number | undefined,
-        payload: body.payload as Record<string, unknown> | undefined,
-      }));
+      return reply.send(await coordinator.appendEvent(userId, sessionId, input));
     } catch (error) {
       return sendCoordinatorError(reply, error);
     }
   });
 
   fastify.post('/v2/vibe/sessions/:sessionId/end', async (request, reply) => {
-    const userId = requireUser(request, reply);
-    if (!userId) return;
-    const { sessionId } = request.params as { sessionId: string };
-    if (!validUuid(sessionId)) return reply.code(400).send({ error: 'sessionId must be a UUID' });
+    const userId = userFor(request, reply);
+    const sessionId = sessionIdFrom(request, reply);
+    if (!userId || !sessionId) return;
     try {
       return reply.send(await coordinator.end(userId, sessionId));
     } catch (error) {
@@ -161,55 +155,25 @@ export default async function vibeSessionsRoutes(
     }
   });
 
-  fastify.post('/v2/vibe/sessions/:sessionId/next', async (request, reply) => {
-    const userId = requireUser(request, reply);
-    if (!userId) return;
-    const { sessionId } = request.params as { sessionId: string };
-    const body = isObject(request.body) ? request.body : {};
-    if (!validUuid(sessionId)) return reply.code(400).send({ error: 'sessionId must be a UUID' });
-    if (body.expectedPlanVersion !== undefined
-      && (!Number.isInteger(body.expectedPlanVersion) || (body.expectedPlanVersion as number) < 1)) {
-      return reply.code(400).send({ error: 'expectedPlanVersion must be a positive integer' });
-    }
-    const unplayable = body.unplayable;
-    if (unplayable !== undefined && !isObject(unplayable)) {
-      return reply.code(400).send({ error: 'unplayable must be an object' });
-    }
-    if (isObject(unplayable)) {
-      if (body.expectedPlanVersion === undefined) {
-        return reply.code(400).send({ error: 'expectedPlanVersion is required when advancing an unplayable item' });
-      }
-      if (!validUuid(unplayable.eventId)
-        || !validUuid(unplayable.planVersionId)
-        || !validUuid(unplayable.trackId)
-        || !Number.isInteger(unplayable.ordinal)
-        || (unplayable.ordinal as number) < 0) {
-        return reply.code(400).send({ error: 'unplayable requires UUID eventId, planVersionId, trackId and a non-negative integer ordinal' });
-      }
-    }
+  fastify.post('/v2/vibe/sessions/:sessionId/advance', async (request, reply) => {
+    const userId = userFor(request, reply);
+    const sessionId = sessionIdFrom(request, reply);
+    const input = parseAdvance(request.body);
+    if (!userId || !sessionId || 'error' in input) return 'error' in input ? validationError(reply, input.error) : undefined;
     try {
-      const expectedPlanVersion = body.expectedPlanVersion as number | undefined;
-      if (isObject(unplayable)) {
-        return reply.send(await coordinator.advancePastUnplayable(userId, sessionId, {
-          expectedPlanVersion: expectedPlanVersion as number,
-          eventId: unplayable.eventId as string,
-          planVersionId: unplayable.planVersionId as string,
-          ordinal: unplayable.ordinal as number,
-          trackId: unplayable.trackId as string,
-        }));
-      }
-      return reply.send(expectedPlanVersion === undefined
-        ? await coordinator.serveNext(userId, sessionId)
-        : await coordinator.serveNext(userId, sessionId, expectedPlanVersion));
+      return reply.send(input.unplayable
+        ? await coordinator.advancePastUnplayable(userId, sessionId, { expectedPlanVersion: input.expectedPlanVersion!, ...input.unplayable })
+        : input.expectedPlanVersion === undefined
+          ? await coordinator.serveNext(userId, sessionId)
+          : await coordinator.serveNext(userId, sessionId, input.expectedPlanVersion));
     } catch (error) {
       return sendCoordinatorError(reply, error);
     }
   });
 }
 
-function sendCoordinatorError(reply: { code: (statusCode: number) => { send: (payload: unknown) => unknown } }, error: unknown) {
-  if (error instanceof VibeSessionNotFoundError) return reply.code(404).send({ error: error.message });
-  if (error instanceof VibePlanNotFoundError) return reply.code(404).send({ error: error.message });
+function sendCoordinatorError(reply: Reply, error: unknown) {
+  if (error instanceof VibeSessionNotFoundError || error instanceof VibePlanNotFoundError) return reply.code(404).send({ error: error.message });
   if (error instanceof VibeSessionLifecycleError) return reply.code(409).send({ error: error.message, code: 'VIBE_SESSION_NOT_ACTIVE' });
   throw error;
 }

backend/src/services/db.service.test.ts

@@ -75,9 +75,7 @@ describe('DbService v2 methods', () => {
         .mockResolvedValueOnce({ rows: [session] })
         .mockResolvedValueOnce({ rows: [{ ...session, status: 'ended' }] });
 
-      await expect(service.createVibeSession({
-        userId: 'user-1', policyVersion: 'v2.1', context: { activity: 'focus' },
-      })).resolves.toEqual(session);
+      await expect(service.createVibeSession({ userId: 'user-1', policyVersion: 'v2.1' })).resolves.toEqual(session);
       await expect(service.getVibeSession('session-1', 'user-1')).resolves.toEqual(session);
       await expect(service.endVibeSession('session-1', 'user-1')).resolves.toMatchObject({ status: 'ended' });
 
@@ -88,17 +86,13 @@ describe('DbService v2 methods', () => {
         'user-1', null, expect.any(String), 'v2.1',
         JSON.stringify({ type: 'discovery', target: 1, progress: 0 }), 0.3, 0.38,
       ]));
-      expect(JSON.parse(clientQuery.mock.calls[3][1][2])).toEqual(expect.objectContaining({
-        activity: 'focus',
-      }));
+      expect(JSON.parse(clientQuery.mock.calls[3][1][2])).toEqual({});
       expect(poolQuery.mock.calls[0][0]).toContain('id = $1 AND user_id = $2');
       expect(poolQuery.mock.calls[1][0]).toContain('COALESCE(ended_at, NOW())');
       expect(poolQuery.mock.calls[1][0]).toContain('CASE WHEN ended_at IS NULL THEN $3 ELSE status END');
     });
 
-    it('normalizes context at the persistence boundary for direct callers', async () => {
-      vi.useFakeTimers();
-      vi.setSystemTime(new Date('2026-08-02T19:00:00.000Z'));
+    it('starts sessions without inventing client context', async () => {
       const { service, clientQuery } = makeTransactionalService();
       const session = { id: 'session-1', user_id: 'user-1', status: 'active' };
       clientQuery
@@ -108,33 +102,13 @@ describe('DbService v2 methods', () => {
         .mockResolvedValueOnce({ rows: [session] }) // insert
         .mockResolvedValueOnce({ rows: [] }); // COMMIT
 
-      try {
-        await service.createVibeSession({
-          userId: 'user-1',
-          policyVersion: 'v2.1',
-          context: {
-            timeZone: 'UTC',
-            activity: 'walking',
-            device: 'phone',
-            exactCoordinates: '53.1959,50.1002',
-            browserTelemetry: { batteryPercent: 4, ipAddress: '192.0.2.1' },
-            localHour: 3,
-            weekday: 1,
-          },
-        });
-
-        const insertParameters = clientQuery.mock.calls[3][1];
-        expect(insertParameters.slice(0, 2)).toEqual(['user-1', null]);
-        expect(JSON.parse(insertParameters[2])).toEqual({
-          timeZone: 'UTC', localHour: 19, weekday: 0, dayKind: 'weekend',
-          activity: 'walking', device: 'phone',
-        });
-        expect(insertParameters.slice(3)).toEqual([
-          'v2.1', JSON.stringify({ type: 'discovery', target: 1, progress: 0 }), 0.3, 0.38,
-        ]);
-      } finally {
-        vi.useRealTimers();
-      }
+      await service.createVibeSession({ userId: 'user-1', policyVersion: 'v2.1' });
+      const insertParameters = clientQuery.mock.calls[3][1];
+      expect(insertParameters.slice(0, 2)).toEqual(['user-1', null]);
+      expect(JSON.parse(insertParameters[2])).toEqual({});
+      expect(insertParameters.slice(3)).toEqual([
+        'v2.1', JSON.stringify({ type: 'discovery', target: 1, progress: 0 }), 0.3, 0.38,
+      ]);
     });
 
     it('replaces an owned active session and writes its terminal event before starting another', async () => {
@@ -189,45 +163,38 @@ describe('DbService v2 methods', () => {
       );
     });
 
-    it('sanitizes and projects an inserted context change atomically with its ledger event', async () => {
+    it('records a non-material event without mutating session context', async () => {
       const { service, clientQuery } = makeTransactionalService();
       const event = {
         id: 'event-1', client_event_id: null, session_id: 'session-1', user_id: 'user-1', track_id: null,
-        type: 'context_changed', occurred_at: new Date(), position_ms: null, duration_ms: null,
-        payload: { context: { activity: 'walking', localHour: 12 } },
+        type: 'progress', occurred_at: new Date(), position_ms: null, duration_ms: null,
+        payload: { source: 'player' },
       };
       clientQuery
         .mockResolvedValueOnce({ rows: [] }) // BEGIN
         .mockResolvedValueOnce({ rows: [{ id: 'session-1', status: 'active' }] }) // lock
         .mockResolvedValueOnce({ rows: [event] }) // insert
-        .mockResolvedValueOnce({ rows: [] }) // session context projection
-        .mockResolvedValueOnce({ rows: [] }) // legacy session-state projection
         .mockResolvedValueOnce({ rows: [] }) // last event timestamp
         .mockResolvedValueOnce({ rows: [] }); // COMMIT
 
       await service.recordVibeEvent({
-        sessionId: 'session-1', userId: 'user-1', type: 'context_changed',
-        payload: {
-          context: { activity: 'walking', exactCoordinates: '53.2,50.1' },
-          rawBrowserTelemetry: { battery: 4 },
-        },
+        sessionId: 'session-1', userId: 'user-1', type: 'progress', payload: { source: 'player' },
       });
 
       const values = clientQuery.mock.calls[2][1];
       const storedPayload = JSON.parse(values[8]);
-      expect(storedPayload).toEqual({ context: expect.objectContaining({ activity: 'walking' }) });
-      expect(storedPayload.context).not.toHaveProperty('exactCoordinates');
-      expect(storedPayload).not.toHaveProperty('rawBrowserTelemetry');
-      expect(clientQuery.mock.calls[3][0]).toContain('SET context = $3::jsonb');
-      expect(clientQuery.mock.calls[4][0]).toContain("jsonb_build_object('context'");
+      expect(storedPayload).toEqual({ source: 'player' });
+      expect(clientQuery.mock.calls.map(([sql]) => String(sql))).not.toContain(
+        expect.stringContaining('SET context = $3::jsonb'),
+      );
     });
 
-    it('does not apply a retry body to an existing context-change event', async () => {
+    it('does not apply a retry body to an existing event', async () => {
       const { service, clientQuery } = makeTransactionalService();
       const canonicalEvent = {
         id: 'event-1', client_event_id: 'client-event-1', session_id: 'session-1', user_id: 'user-1', track_id: null,
-        type: 'context_changed', occurred_at: new Date(), position_ms: null, duration_ms: null,
-        payload: { context: { activity: 'focus', localHour: 12 } },
+        type: 'progress', occurred_at: new Date(), position_ms: null, duration_ms: null,
+        payload: { source: 'player' },
       };
       clientQuery
         .mockResolvedValueOnce({ rows: [] }) // BEGIN
@@ -236,8 +203,8 @@ describe('DbService v2 methods', () => {
         .mockResolvedValueOnce({ rows: [] }); // COMMIT
 
       const result = await service.recordVibeEvent({
-        sessionId: 'session-1', userId: 'user-1', clientEventId: 'client-event-1', type: 'context_changed',
-        payload: { context: { activity: 'workout', exactCoordinates: '53.2,50.1' } },
+        sessionId: 'session-1', userId: 'user-1', clientEventId: 'client-event-1', type: 'progress',
+        payload: { source: 'retry' },
       });
 
       expect(result).toEqual({ event: canonicalEvent, inserted: false });

backend/src/services/db.service.ts

@@ -6,7 +6,6 @@ import { fileURLToPath } from 'url';
 import { dirname, join } from 'path';
 import { Pool, PoolClient } from 'pg';
 import { SearchService } from './search.service.js';
-import { normalizeVibeContext, normalizeVibeEventPayload } from './vibe-context.service.js';
 
 /** Anything with a `.query()` — either the shared Pool or a checked-out client. */
 type Queryable = Pool | PoolClient;
@@ -1515,18 +1514,12 @@ export class DbService {
     userId: string;
     policyVersion: string;
     seedTrackId?: string | null;
-    context?: Record<string, unknown>;
     profile?: {
       goals: Record<string, unknown>;
       explorationCoefficient: number;
       discoveryRadius: number;
     };
   }): Promise<VibeSession> {
-    // DbService is also used directly by workers and migrations. Keep the
-    // durable storage boundary canonical even when callers bypass the HTTP
-    // coordinator, so opaque or precise client telemetry can never become
-    // session context.
-    const canonicalContext = normalizeVibeContext(params.context ?? {});
     return this.withTransaction(async (client) => {
       // Serialize starts for one listener even when there is no active row to
       // lock yet. The row lock below then safely replaces any prior session.
@@ -1568,7 +1561,7 @@ export class DbService {
         [
           params.userId,
           params.seedTrackId ?? null,
-          JSON.stringify(canonicalContext),
+          '{}',
           params.policyVersion,
           JSON.stringify(params.profile?.goals ?? { type: 'discovery', target: 1, progress: 0 }),
           params.profile?.explorationCoefficient ?? 0.3,
@@ -1615,29 +1608,6 @@ export class DbService {
     return (res.rows[0] as VibeSessionProfile | undefined) ?? null;
   }
 
-  /** Replace only the coarse, sanitised context attached to an active session.
-   * The immutable context_changed event remains the audit trail. */
-  async updateVibeSessionContext(sessionId: string, userId: string, context: Record<string, unknown>): Promise<void> {
-    const canonicalContext = normalizeVibeContext(context);
-    await this.withTransaction(async client => {
-      const updated = await client.query(
-        `UPDATE vibe_sessions SET context = $3::jsonb, last_event_at = NOW()
-         WHERE id = $1 AND user_id = $2 AND status = 'active'
-         RETURNING id`,
-        [sessionId, userId, JSON.stringify(canonicalContext)],
-      );
-      if (!updated.rows[0]) throw new Error('Vibe session was not found or is not owned by this user');
-      await client.query(
-        `UPDATE session_state
-         SET context = COALESCE($3::jsonb->>'activity', $3::jsonb->>'device'),
-             state_vector = state_vector || jsonb_build_object('context', $3::jsonb),
-             last_interaction = NOW()
-         WHERE session_id = $1 AND user_id = $2`,
-        [sessionId, userId, JSON.stringify(canonicalContext)],
-      );
-    });
-  }
-
   /**
    * Project unknown-track feedback into the session exploration controls.
    * This deliberately runs behind its own projection marker: the immutable
@@ -1825,10 +1795,6 @@ export class DbService {
     durationMs?: number | null;
     payload?: Record<string, unknown>;
   }): Promise<RecordedVibeEvent> {
-    // This service is also called by jobs and tests which bypass the HTTP
-    // route. Preserve the context privacy boundary at the final point before
-    // an immutable ledger write.
-    const payload = normalizeVibeEventPayload(params.type, params.payload);
     return this.withTransaction(async (client) => {
       // A session-row lock serializes both event writes and terminal state
       // transitions. In particular, it avoids the READ COMMITTED CTE snapshot
@@ -1880,7 +1846,7 @@ export class DbService {
           occurredAt,
           params.positionMs ?? null,
           params.durationMs ?? null,
-          JSON.stringify(payload ?? {}),
+          JSON.stringify(params.payload ?? {}),
         ]
       );
       const event = insertRes.rows[0] as VibeEvent | undefined;
@@ -1889,8 +1855,6 @@ export class DbService {
       }
 
       await this.projectVibeFeedback(event, client);
-      await this.projectVibeContextChanged(event, client);
-
       await client.query(
         `UPDATE vibe_sessions
          SET last_event_at = GREATEST(last_event_at, $2::timestamptz)
@@ -1901,30 +1865,6 @@ export class DbService {
     });
   }
 
-  /** Apply the context projection in the same transaction as its *inserted*
-   * ledger event. A client-event retry returns before this method, so its body
-   * can never overwrite session state with a different context. */
-  private async projectVibeContextChanged(event: VibeEvent, client: PoolClient): Promise<void> {
-    if (event.type !== 'context_changed') return;
-    const context = event.payload?.context;
-    if (!context || typeof context !== 'object' || Array.isArray(context)) return;
-    const canonicalContext = context as Record<string, unknown>;
-    await client.query(
-      `UPDATE vibe_sessions
-       SET context = $3::jsonb
-       WHERE id = $1 AND user_id = $2 AND status = 'active'`,
-      [event.session_id, event.user_id, JSON.stringify(canonicalContext)],
-    );
-    await client.query(
-      `UPDATE session_state
-       SET context = COALESCE($3::jsonb->>'activity', $3::jsonb->>'device'),
-           state_vector = state_vector || jsonb_build_object('context', $3::jsonb),
-           last_interaction = NOW()
-       WHERE session_id = $1 AND user_id = $2`,
-      [event.session_id, event.user_id, JSON.stringify(canonicalContext)],
-    );
-  }
-
   /**
    * Materialize Vibe feedback into the listener inputs used by the incumbent
    * director. The projection marker and every write share the event's

backend/src/services/session-director.service.ts

@@ -1636,7 +1636,7 @@ export class SessionDirector {
     return scored.map(s => s.candidate);
   }
 
-  // session_state is otherwise only written once at /v2/vibe/start — persist the
+  // session_state is otherwise only written once when a Vibe session starts — persist the
   // freshly-computed state vector here so it evolves across the session instead of
   // buildState always reading back the boot defaults.
   async persistState(sessionId: string, userId: string, state: GeneratorContext['state']): Promise<void> {

backend/src/services/vibe-context.service.test.ts

@@ -1,36 +0,0 @@
-import { describe, expect, it } from 'vitest';
-import { initialVibeState, normalizeVibeContext, normalizeVibeEventPayload } from './vibe-context.service.js';
-
-describe('Vibe context', () => {
-  it('keeps only coarse structured values and derives time on the server', () => {
-    const context = normalizeVibeContext({
-      timeZone: 'UTC', activity: 'workout', device: 'headphones',
-      exactCoordinates: '53.2,50.1', localHour: 3,
-    }, new Date('2026-08-02T19:00:00.000Z'));
-
-    expect(context).toMatchObject({ localHour: 19, weekday: 0, dayKind: 'weekend', activity: 'workout' });
-    expect(context).not.toHaveProperty('exactCoordinates');
-    expect(context).not.toHaveProperty('localHour', 3);
-  });
-
-  it('uses context only as a bounded initial prior and gives focus a comfort goal', () => {
-    const state = initialVibeState(normalizeVibeContext({ activity: 'focus' }, new Date('2026-08-03T12:00:00.000Z')));
-    expect(state.energy).toBeGreaterThan(0);
-    expect(state.energy).toBeLessThan(1);
-    expect(state.sessionGoal).toEqual({ type: 'familiar', target: 1, progress: 0 });
-  });
-
-  it('persists only canonical context for context-change events', () => {
-    const payload = normalizeVibeEventPayload('context_changed', {
-      context: { activity: 'walking', exactCoordinates: '53.2,50.1', adId: 'do-not-store' },
-      rawBrowserTelemetry: { battery: 4 },
-    });
-
-    expect(payload).toEqual({
-      context: expect.objectContaining({ activity: 'walking' }),
-    });
-    expect(payload).not.toHaveProperty('rawBrowserTelemetry');
-    expect((payload?.context as Record<string, unknown>)).not.toHaveProperty('exactCoordinates');
-    expect((payload?.context as Record<string, unknown>)).not.toHaveProperty('adId');
-  });
-});

backend/src/services/vibe-context.service.ts

@@ -1,120 +0,0 @@
-/**
- * Coarse, opt-in context accepted by the durable Vibe API.  It deliberately
- * has no precise location, identifiers, or browser telemetry: clients can
- * supply a hint, but the server owns the time fields and can ignore all of it.
- */
-export const VIBE_CONTEXT_VALUES = {
-  device: ['desktop', 'phone', 'speaker', 'car', 'headphones'] as const,
-  activity: ['focus', 'relax', 'walking', 'workout', 'social', 'unknown'] as const,
-  locationCategory: ['home', 'work', 'gym', 'travel', 'unknown'] as const,
-  weather: ['clear', 'rain', 'snow', 'hot', 'cold', 'unknown'] as const,
-  source: ['current_track', 'artist', 'genre', 'surprise', 'resume'] as const,
-};
-
-export interface VibeContext {
-  timeZone?: string;
-  localHour?: number;
-  weekday?: number;
-  dayKind?: 'weekday' | 'weekend' | 'holiday';
-  device?: (typeof VIBE_CONTEXT_VALUES.device)[number];
-  activity?: (typeof VIBE_CONTEXT_VALUES.activity)[number];
-  locationCategory?: (typeof VIBE_CONTEXT_VALUES.locationCategory)[number];
-  weather?: (typeof VIBE_CONTEXT_VALUES.weather)[number];
-  source?: (typeof VIBE_CONTEXT_VALUES.source)[number];
-}
-
-export interface InitialVibeState {
-  contextLabel: string | undefined;
-  energy: number;
-  noveltyHunger: number;
-  explorationCoefficient: number;
-  discoveryRadius: number;
-  sessionGoal: { type: 'surprise' | 'familiar' | 'discovery' | 'artist_introduction'; target: number; progress: number };
-}
-
-const hasValue = <T extends readonly string[]>(values: T, value: unknown): value is T[number] =>
-  typeof value === 'string' && (values as readonly string[]).includes(value);
-
-function serverTime(timeZone?: string, now = new Date()): Pick<VibeContext, 'timeZone' | 'localHour' | 'weekday' | 'dayKind'> {
-  // Intl rejects bad IANA names. Falling back to the server clock is safe and
-  // still makes time a weak prior rather than client-controlled fact.
-  let zone: string | undefined;
-  try {
-    if (timeZone) new Intl.DateTimeFormat('en-US', { timeZone }).format(now);
-    zone = timeZone;
-  } catch { /* server-local fallback */ }
-  const parts = new Intl.DateTimeFormat('en-US', {
-    timeZone: zone, hour: 'numeric', weekday: 'short', hourCycle: 'h23',
-  }).formatToParts(now);
-  const hour = Number(parts.find(part => part.type === 'hour')?.value ?? now.getHours());
-  const weekdayName = parts.find(part => part.type === 'weekday')?.value;
-  const weekday = ['Sun', 'Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat'].indexOf(weekdayName ?? '');
-  return {
-    ...(zone ? { timeZone: zone } : {}),
-    localHour: Number.isInteger(hour) ? hour : now.getHours(),
-    weekday: weekday >= 0 ? weekday : now.getDay(),
-    dayKind: ([0, 6].includes(weekday >= 0 ? weekday : now.getDay()) ? 'weekend' : 'weekday'),
-  };
-}
-
-/** Remove unknown fields and derive time server-side.  This preserves old
- * clients that send an empty object while preventing opaque context blobs from
- * becoming a permanent behavioural profile. */
-export function normalizeVibeContext(input: Record<string, unknown> = {}, now = new Date()): VibeContext {
-  const time = serverTime(typeof input.timeZone === 'string' ? input.timeZone : undefined, now);
-  return {
-    ...time,
-    ...(hasValue(VIBE_CONTEXT_VALUES.device, input.device) ? { device: input.device } : {}),
-    ...(hasValue(VIBE_CONTEXT_VALUES.activity, input.activity) ? { activity: input.activity } : {}),
-    ...(hasValue(VIBE_CONTEXT_VALUES.locationCategory, input.locationCategory) ? { locationCategory: input.locationCategory } : {}),
-    ...(hasValue(VIBE_CONTEXT_VALUES.weather, input.weather) ? { weather: input.weather } : {}),
-    ...(hasValue(VIBE_CONTEXT_VALUES.source, input.source) ? { source: input.source } : {}),
-  };
-}
-
-/**
- * Context changes are the only event payload with a structured, durable
- * context body. Keep their ledger representation intentionally tiny: callers
- * cannot smuggle precise location or arbitrary browser telemetry into an
- * immutable event by adding sibling fields or unknown context keys.
- */
-export function normalizeVibeEventPayload(
-  type: string,
-  payload?: Record<string, unknown>,
-): Record<string, unknown> | undefined {
-  if (type !== 'context_changed') return payload;
-  const context = payload?.context;
-  if (!context || typeof context !== 'object' || Array.isArray(context)) return {};
-  return { context: normalizeVibeContext(context as Record<string, unknown>) };
-}
-
-/** Context is intentionally a gentle prior. It can nudge the initial arc but
- * never overrides observed playback behaviour. */
-export function initialVibeState(context: VibeContext): InitialVibeState {
-  const activityEnergy: Record<string, number> = {
-    focus: 0.42, relax: 0.34, walking: 0.58, workout: 0.72, social: 0.62, unknown: 0.5,
-  };
-  const hour = context.localHour ?? 12;
-  const hourEnergy = hour < 6 ? 0.32 : hour < 10 ? 0.46 : hour >= 22 ? 0.38 : 0.52;
-  const activity = context.activity ?? 'unknown';
-  const energy = Math.max(0, Math.min(1, activityEnergy[activity] * 0.7 + hourEnergy * 0.3));
-  const goal = activity === 'focus' || activity === 'relax'
-    ? 'familiar'
-    : activity === 'workout' || activity === 'walking' ? 'surprise' : 'discovery';
-  return {
-    contextLabel: context.activity ?? context.device,
-    energy,
-    noveltyHunger: 0.3,
-    explorationCoefficient: 0.3,
-    discoveryRadius: 0.38,
-    sessionGoal: { type: goal, target: 1, progress: 0 },
-  };
-}
-
-export function isValidVibeContext(input: Record<string, unknown>): boolean {
-  const scalar = (key: keyof typeof VIBE_CONTEXT_VALUES) => input[key] === undefined
-    || hasValue(VIBE_CONTEXT_VALUES[key], input[key]);
-  return (input.timeZone === undefined || typeof input.timeZone === 'string')
-    && scalar('device') && scalar('activity') && scalar('locationCategory')
-    && scalar('weather') && scalar('source');
-}

backend/src/services/vibe-session-coordinator.service.test.ts

@@ -14,7 +14,7 @@ const EVENT_ID = '33333333-3333-4333-8333-333333333333';
 function session(status: 'active' | 'ended' = 'active') {
   return {
     id: SESSION_ID, user_id: 'user-1', status, seed_track_id: null,
-    context: { activity: 'focus' }, policy_version: DEFAULT_VIBE_POLICY_VERSION,
+    context: {}, policy_version: DEFAULT_VIBE_POLICY_VERSION,
     started_at: new Date('2026-01-01T00:00:00.000Z'),
     last_event_at: new Date('2026-01-01T00:00:00.000Z'), ended_at: status === 'ended' ? new Date() : null,
   } as any;
@@ -63,15 +63,13 @@ describe('VibeSessionCoordinator', () => {
   it('creates an authoritative session, shadow state, initial plan revision, and ledger events', async () => {
     const { db, director, coordinator } = setup();
 
-    const response = await coordinator.start('user-1', {
-      context: { activity: 'focus' }, intent: 'deep-work',
-    });
+    const response = await coordinator.start('user-1', {});
 
     expect(response).toMatchObject({ sessionId: SESSION_ID, planVersion: 1, now: { track_id: TRACK_ID } });
     expect(db.createVibeSession).toHaveBeenCalledWith(expect.objectContaining({
       userId: 'user-1', policyVersion: DEFAULT_VIBE_POLICY_VERSION,
     }));
-    expect(db.createSessionState).toHaveBeenCalledWith('user-1', 'focus', expect.any(Object), SESSION_ID);
+    expect(db.createSessionState).toHaveBeenCalledWith('user-1', undefined, expect.any(Object), SESSION_ID);
     expect(director.buildPlan).toHaveBeenCalledWith('user-1', SESSION_ID, undefined);
     expect(db.publishVibePlan).toHaveBeenCalledWith(expect.objectContaining({
       sessionId: SESSION_ID, version: 1, reason: 'session_started',
@@ -154,38 +152,14 @@ describe('VibeSessionCoordinator', () => {
     expect(response).toMatchObject({ replanned: true, replanReason: 'feedback:completed', planVersion: 2 });
   });
 
-  it('normalizes context before the immutable event write', async () => {
-    const { db, coordinator } = setup();
-    (db.recordVibeEvent as any).mockResolvedValueOnce({
-      event: { id: 'event-1', type: 'context_changed', payload: {} }, inserted: true,
-    });
-
-    await coordinator.appendEvent('user-1', SESSION_ID, {
-      type: 'context_changed',
-      payload: {
-        context: { activity: 'walking', exactCoordinates: '53.2,50.1' },
-        rawBrowserTelemetry: { battery: 4 },
-      },
-    });
-
-    expect(db.recordVibeEvent).toHaveBeenCalledWith(expect.objectContaining({
-      payload: {
-        context: expect.objectContaining({ activity: 'walking' }),
-      },
-    }));
-    const payload = (db.recordVibeEvent as any).mock.calls[0][0].payload;
-    expect(payload).not.toHaveProperty('rawBrowserTelemetry');
-    expect(payload.context).not.toHaveProperty('exactCoordinates');
-  });
-
-  it('creates the durable profile from the initial context goal', async () => {
+  it('creates a neutral durable profile until listening behaviour provides evidence', async () => {
     const { db, coordinator } = setup();
 
-    await coordinator.start('user-1', { context: { activity: 'focus' } });
+    await coordinator.start('user-1', {});
 
     expect(db.createVibeSession).toHaveBeenCalledWith(expect.objectContaining({
       profile: expect.objectContaining({
-        goals: { type: 'familiar', target: 1, progress: 0 },
+        goals: { type: 'discovery', target: 1, progress: 0 },
         explorationCoefficient: 0.3,
         discoveryRadius: 0.38,
       }),

backend/src/services/vibe-session-coordinator.service.ts

@@ -1,12 +1,6 @@
 import { DbService, VibeEvent, VibePlan, VibeSession } from './db.service.js';
 import { SessionDirector } from './session-director.service.js';
 import { Candidate } from './generators.service.js';
-import {
-  initialVibeState,
-  normalizeVibeContext,
-  normalizeVibeEventPayload,
-  VibeContext,
-} from './vibe-context.service.js';
 
 /**
  * This is deliberately a narrow bridge between the durable Vibe ledger and
@@ -16,7 +10,7 @@ import {
 export const DEFAULT_VIBE_POLICY_VERSION = 'vibe-v2-initial';
 
 export const VIBE_EVENT_TYPES = [
-  'session_started', 'session_resumed', 'session_ended', 'context_changed',
+  'session_started', 'session_resumed', 'session_ended',
   'plan_published', 'track_served', 'playback_started', 'progress', 'completed',
   'skipped', 'disliked', 'kept', 'favourite_added', 'queue_removed',
   'manual_search', 'album_opened', 'artist_opened', 'playlist_added',
@@ -27,9 +21,6 @@ export type VibeEventType = (typeof VIBE_EVENT_TYPES)[number];
 
 export interface StartVibeSessionInput {
   seedTrackId?: string;
-  context?: VibeContext | Record<string, unknown>;
-  intent?: string;
-  policyVersion?: string;
   resumeSessionId?: string;
 }
 
@@ -79,14 +70,19 @@ export class VibeSessionCoordinator {
 
   async start(userId: string, input: StartVibeSessionInput): Promise<VibeSessionResponse> {
     if (input.resumeSessionId) return this.resume(userId, input.resumeSessionId);
-    const context = normalizeVibeContext({ ...(input.context ?? {}) });
-    const initialState = initialVibeState(context);
-    const policyVersion = input.policyVersion ?? DEFAULT_VIBE_POLICY_VERSION;
+    // Vibe has no reliable device/activity/location signal. Start from neutral
+    // recommendation state and let actual listening behaviour shape the plan.
+    const initialState = {
+      energy: 0.5,
+      noveltyHunger: 0.3,
+      explorationCoefficient: 0.3,
+      discoveryRadius: 0.38,
+      sessionGoal: { type: 'discovery' as const, target: 1, progress: 0 },
+    };
     const session = await this.db.createVibeSession({
       userId,
-      policyVersion,
+      policyVersion: DEFAULT_VIBE_POLICY_VERSION,
       seedTrackId: input.seedTrackId ?? null,
-      context: { ...context },
       profile: {
         goals: initialState.sessionGoal,
         explorationCoefficient: initialState.explorationCoefficient,
@@ -99,14 +95,13 @@ export class VibeSessionCoordinator {
     // session while the durable tables remain the source of truth.
     await this.db.createSessionState(
       userId,
-      initialState.contextLabel ?? input.intent,
+      undefined,
       {
         energy: initialState.energy,
         noveltyHunger: initialState.noveltyHunger,
         explorationCoefficient: initialState.explorationCoefficient,
         discoveryRadius: initialState.discoveryRadius,
         sessionGoal: initialState.sessionGoal,
-        context,
       },
       session.id,
     );
@@ -114,7 +109,7 @@ export class VibeSessionCoordinator {
       sessionId: session.id,
       userId,
       type: 'session_started',
-      payload: { policyVersion, context, intent: input.intent ?? null },
+      payload: { policyVersion: DEFAULT_VIBE_POLICY_VERSION },
     });
 
     const candidates = await this.director.buildPlan(userId, session.id, input.seedTrackId);
@@ -128,8 +123,7 @@ export class VibeSessionCoordinator {
         reason: 'session_started',
         stateSnapshot: state,
         objectiveSnapshot: {
-          policyVersion,
-          intent: input.intent ?? null,
+          policyVersion: DEFAULT_VIBE_POLICY_VERSION,
           horizonTracks: candidates.length,
           ...(candidates[0]?.plan?.objective ?? {}),
         },
@@ -203,7 +197,6 @@ export class VibeSessionCoordinator {
       // events are immutable. The DB repeats this boundary for non-HTTP
       // callers; keeping it here also makes coordinator callers see exactly
       // what will be persisted.
-      const payload = normalizeVibeEventPayload(input.type, input.payload);
       const result = await this.db.recordVibeEvent({
         sessionId,
         userId,
@@ -213,7 +206,7 @@ export class VibeSessionCoordinator {
         occurredAt: input.occurredAt,
         positionMs: input.positionMs,
         durationMs: input.durationMs,
-        payload,
+        payload: input.payload,
       });
       // The ledger write is authoritative; this idempotent projection updates
       // exploration only after the exact event exists. Keep the compatibility