feat(vibe): adapt sessions to context and exploration

backend/src/db/migrations.test.ts

@@ -43,3 +43,19 @@ describe('Vibe durable session migration', () => {
     expect(migration!.sql).toContain('idx_vibe_events_user_occurred');
   });
 });
+
+describe('Vibe context memory migration', () => {
+  it('adds bounded session exploration state and exactly-once projection storage', () => {
+    const migration = MIGRATIONS.find(({ id }) => id === '20260802_vibe_context_memory_exploration');
+    expect(migration?.sql).toContain('CREATE TABLE IF NOT EXISTS vibe_session_profiles');
+    expect(migration?.sql).toContain('exploration_coefficient');
+    expect(migration?.sql).toContain('vibe_session_feedback_projections');
+  });
+
+  it('backfills profiles for durable sessions created before context memory', () => {
+    const migration = MIGRATIONS.find(({ id }) => id === '20260802_vibe_session_profile_backfill');
+    expect(migration?.sql).toContain('INSERT INTO vibe_session_profiles');
+    expect(migration?.sql).toContain('SELECT id, user_id FROM vibe_sessions');
+    expect(migration?.sql).toContain('ON CONFLICT (session_id) DO NOTHING');
+  });
+});

backend/src/db/migrations.ts

@@ -720,4 +720,43 @@ export const MIGRATIONS: Migration[] = [
       );
     `,
   },
+  {
+    // Session-specific exploration, goals, and deliberately lossy session
+    // fingerprints are derived from the immutable Vibe ledger. Keeping them
+    // separate from listener_beliefs prevents a transient session from
+    // rewriting permanent taste.
+    id: '20260802_vibe_context_memory_exploration',
+    sql: `
+      CREATE TABLE IF NOT EXISTS vibe_session_profiles (
+        session_id UUID PRIMARY KEY REFERENCES vibe_sessions(id) ON DELETE CASCADE,
+        user_id UUID NOT NULL,
+        fingerprint JSONB NOT NULL DEFAULT '{}'::jsonb,
+        goals JSONB NOT NULL DEFAULT '{"type":"discovery","target":1,"progress":0}'::jsonb,
+        exploration_coefficient REAL NOT NULL DEFAULT 0.30
+          CHECK (exploration_coefficient >= 0 AND exploration_coefficient <= 1),
+        discovery_radius REAL NOT NULL DEFAULT 0.38
+          CHECK (discovery_radius >= 0 AND discovery_radius <= 1),
+        updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+      );
+      CREATE INDEX IF NOT EXISTS idx_vibe_session_profiles_user_updated
+        ON vibe_session_profiles (user_id, updated_at DESC);
+
+      CREATE TABLE IF NOT EXISTS vibe_session_feedback_projections (
+        event_id UUID PRIMARY KEY REFERENCES vibe_events(id) ON DELETE CASCADE,
+        projected_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+      );
+    `,
+  },
+  {
+    // The profile table was introduced after durable sessions. Backfill every
+    // pre-existing session before feedback can claim its exactly-once marker;
+    // newly created sessions receive their context-derived initial goals in
+    // createVibeSession's transaction.
+    id: '20260802_vibe_session_profile_backfill',
+    sql: `
+      INSERT INTO vibe_session_profiles (session_id, user_id)
+      SELECT id, user_id FROM vibe_sessions
+      ON CONFLICT (session_id) DO NOTHING;
+    `,
+  },
 ];

backend/src/db/schema.sql

@@ -543,6 +543,23 @@ CREATE TABLE IF NOT EXISTS vibe_sessions (
 CREATE INDEX IF NOT EXISTS idx_vibe_sessions_user_last_event
     ON vibe_sessions (user_id, last_event_at DESC);
 
+-- Compact, derived memory for the session director. Fingerprints are a
+-- deliberately lossy description of session shape (not a track list) and are
+-- used only as a soft freshness signal against recent sessions.
+CREATE TABLE IF NOT EXISTS vibe_session_profiles (
+    session_id UUID PRIMARY KEY REFERENCES vibe_sessions(id) ON DELETE CASCADE,
+    user_id UUID NOT NULL,
+    fingerprint JSONB NOT NULL DEFAULT '{}'::jsonb,
+    goals JSONB NOT NULL DEFAULT '{"type":"discovery","target":1,"progress":0}'::jsonb,
+    exploration_coefficient REAL NOT NULL DEFAULT 0.30
+        CHECK (exploration_coefficient >= 0 AND exploration_coefficient <= 1),
+    discovery_radius REAL NOT NULL DEFAULT 0.38
+        CHECK (discovery_radius >= 0 AND discovery_radius <= 1),
+    updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+);
+CREATE INDEX IF NOT EXISTS idx_vibe_session_profiles_user_updated
+    ON vibe_session_profiles (user_id, updated_at DESC);
+
 CREATE TABLE IF NOT EXISTS vibe_events (
     id              UUID PRIMARY KEY DEFAULT gen_random_uuid(),
     client_event_id UUID,
@@ -570,6 +587,14 @@ CREATE TABLE IF NOT EXISTS vibe_event_projections (
     projected_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
 );
 
+-- Separate from listener-belief projection because exploration is session
+-- state. It lets a failed post-event replan safely retry the exact same
+-- adaptation without counting the feedback twice.
+CREATE TABLE IF NOT EXISTS vibe_session_feedback_projections (
+    event_id UUID PRIMARY KEY REFERENCES vibe_events(id) ON DELETE CASCADE,
+    projected_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+);
+
 CREATE TABLE IF NOT EXISTS vibe_plan_versions (
     id                 UUID PRIMARY KEY DEFAULT gen_random_uuid(),
     session_id         UUID NOT NULL REFERENCES vibe_sessions(id) ON DELETE CASCADE,

backend/src/db/types.ts

@@ -258,3 +258,16 @@ export interface VibePlanItem {
 export interface VibePlan extends VibePlanVersion {
   items: VibePlanItem[];
 }
+
+/** Derived session-director memory. The ledger remains authoritative; this
+ * compact row makes fingerprints, bounded goals, and exploration state cheap
+ * to read while planning. */
+export interface VibeSessionProfile {
+  session_id: string;
+  user_id: string;
+  fingerprint: Record<string, unknown>;
+  goals: Record<string, unknown>;
+  exploration_coefficient: number;
+  discovery_radius: number;
+  updated_at: Date;
+}