feat(chat): unify session gateway with stable IDs and a single WS protocol

The frontend previously juggled placeholder IDs, provider-native IDs, and session_created handoffs, which caused race conditions and provider-specific branching. This introduces app-allocated session IDs, a chat run registry with event replay, delta sidebar updates, and one kind-based websocket contract so the UI can treat every provider the same while JSONL remains the source of truth.

server/modules/database/migrations.ts

@@ -382,6 +382,25 @@ const rebuildSessionsTableWithProjectSchema = (db: Database): void => {
   }
 };
 
+/**
+ * Adds the `provider_session_id` mapping column used by the session gateway.
+ *
+ * Rows that existed before this migration were always keyed directly by the
+ * provider-native session id, so backfilling `provider_session_id` with
+ * `session_id` keeps every legacy row resolvable through the new mapping.
+ */
+const addProviderSessionIdMapping = (db: Database): void => {
+  const sessionsTableInfo = getTableInfo(db, 'sessions');
+  const columnNames = sessionsTableInfo.map((column) => column.name);
+
+  addColumnToTableIfNotExists(db, 'sessions', columnNames, 'provider_session_id', 'TEXT');
+  db.exec(`
+    UPDATE sessions
+    SET provider_session_id = session_id
+    WHERE provider_session_id IS NULL
+  `);
+};
+
 const ensureProjectsForSessionPaths = (db: Database): void => {
   if (!tableExists(db, 'sessions')) {
     return;
@@ -428,9 +447,11 @@ export const runMigrations = (db: Database) => {
     migrateLegacyWorkspaceTableIntoProjects(db);
     rebuildSessionsTableWithProjectSchema(db);
     migrateLegacySessionNames(db);
+    addProviderSessionIdMapping(db);
     ensureProjectsForSessionPaths(db);
 
     db.exec('CREATE INDEX IF NOT EXISTS idx_session_ids_lookup ON sessions(session_id)');
+    db.exec('CREATE INDEX IF NOT EXISTS idx_sessions_provider_session_id ON sessions(provider_session_id)');
     db.exec('CREATE INDEX IF NOT EXISTS idx_sessions_project_path ON sessions(project_path)');
     db.exec('CREATE INDEX IF NOT EXISTS idx_sessions_is_archived ON sessions(isArchived)');
     db.exec('CREATE INDEX IF NOT EXISTS idx_projects_is_starred ON projects(isStarred)');

server/modules/database/repositories/sessions.db.ts

@@ -5,6 +5,7 @@ import { normalizeProjectPath } from '@/shared/utils.js';
 type SessionRow = {
   session_id: string;
   provider: string;
+  provider_session_id: string | null;
   project_path: string | null;
   jsonl_path: string | null;
   custom_name: string | null;
@@ -13,10 +14,8 @@ type SessionRow = {
   updated_at: string;
 };
 
-type SessionMetadataLookupRow = Pick<
-  SessionRow,
-  'session_id' | 'provider' | 'project_path' | 'jsonl_path' | 'custom_name' | 'isArchived' | 'created_at' | 'updated_at'
->;
+const SESSION_ROW_COLUMNS =
+  'session_id, provider, provider_session_id, project_path, jsonl_path, custom_name, isArchived, created_at, updated_at';
 
 function normalizeTimestamp(value?: string): string | null {
   if (!value) return null;
@@ -35,8 +34,16 @@ function normalizeProjectPathForProvider(provider: string, projectPath: string):
 }
 
 export const sessionsDb = {
+  /**
+   * Upserts one session row discovered on disk by a provider synchronizer.
+   *
+   * The given id is the provider-native session id. Rows are keyed by
+   * `provider_session_id` so a session that was first created by the app
+   * (with an app-allocated `session_id`) is updated in place once its
+   * transcript shows up on disk, instead of producing a duplicate row.
+   */
   createSession(
-    sessionId: string,
+    providerSessionId: string,
     provider: string,
     projectPath: string,
     customName?: string,
@@ -53,19 +60,54 @@ export const sessionsDb = {
     // since it's a foreign key in the sessions table.
     projectsDb.createProjectPath(normalizedProjectPath);
 
+    const existing = db
+      .prepare(
+        `SELECT session_id FROM sessions
+         WHERE provider_session_id = ? AND provider = ?
+         LIMIT 1`
+      )
+      .get(providerSessionId, provider) as { session_id: string } | undefined;
+
+    if (existing) {
+      db.prepare(
+        `UPDATE sessions SET
+           provider = ?,
+           updated_at = COALESCE(?, CURRENT_TIMESTAMP),
+           project_path = ?,
+           jsonl_path = ?,
+           isArchived = 0,
+           custom_name = COALESCE(?, custom_name)
+         WHERE session_id = ?`
+      ).run(
+        provider,
+        updatedAtValue,
+        normalizedProjectPath,
+        jsonlPath ?? null,
+        customName ?? null,
+        existing.session_id
+      );
+
+      return existing.session_id;
+    }
+
+    // Sessions created outside the app (directly via the provider CLI) are
+    // keyed by the provider-native id for both columns. The ON CONFLICT path
+    // covers legacy rows that predate the provider_session_id mapping.
     db.prepare(
-      `INSERT INTO sessions (session_id, provider, custom_name, project_path, jsonl_path, isArchived, created_at, updated_at)
-       VALUES (?, ?, ?, ?, ?, 0, COALESCE(?, CURRENT_TIMESTAMP), COALESCE(?, CURRENT_TIMESTAMP))
+      `INSERT INTO sessions (session_id, provider, provider_session_id, custom_name, project_path, jsonl_path, isArchived, created_at, updated_at)
+       VALUES (?, ?, ?, ?, ?, ?, 0, COALESCE(?, CURRENT_TIMESTAMP), COALESCE(?, CURRENT_TIMESTAMP))
        ON CONFLICT(session_id) DO UPDATE SET
          provider = excluded.provider,
+         provider_session_id = excluded.provider_session_id,
          updated_at = excluded.updated_at,
          project_path = excluded.project_path,
          jsonl_path = excluded.jsonl_path,
          isArchived = 0,
          custom_name = COALESCE(excluded.custom_name, sessions.custom_name)`
     ).run(
-      sessionId,
+      providerSessionId,
       provider,
+      providerSessionId,
       customName ?? null,
       normalizedProjectPath,
       jsonlPath ?? null,
@@ -73,9 +115,77 @@ export const sessionsDb = {
       updatedAtValue
     );
 
+    return providerSessionId;
+  },
+
+  /**
+   * Inserts one app-allocated session row before any provider run happens.
+   *
+   * The session gateway uses this when the frontend starts a brand-new chat:
+   * `session_id` is the stable app-facing id, while `provider_session_id`
+   * stays NULL until the provider runtime announces its own id and
+   * `assignProviderSessionId` records the mapping.
+   */
+  createAppSession(sessionId: string, provider: string, projectPath: string): string {
+    const db = getConnection();
+    const normalizedProjectPath = normalizeProjectPathForProvider(provider, projectPath);
+
+    projectsDb.createProjectPath(normalizedProjectPath);
+
+    db.prepare(
+      `INSERT INTO sessions (session_id, provider, provider_session_id, custom_name, project_path, jsonl_path, isArchived, created_at, updated_at)
+       VALUES (?, ?, NULL, NULL, ?, NULL, 0, CURRENT_TIMESTAMP, CURRENT_TIMESTAMP)`
+    ).run(sessionId, provider, normalizedProjectPath);
+
     return sessionId;
   },
 
+  /**
+   * Records the provider-native session id for one app-allocated session.
+   *
+   * If the filesystem watcher indexed the provider transcript before this
+   * mapping was recorded (a duplicate row keyed by the provider id exists),
+   * the duplicate is merged into the app row: its transcript path and name
+   * are adopted and the duplicate row is removed. Runs in a transaction so
+   * the sidebar can never observe both rows at once.
+   */
+  assignProviderSessionId(sessionId: string, providerSessionId: string): void {
+    const db = getConnection();
+
+    const merge = db.transaction(() => {
+      const duplicate = db
+        .prepare(
+          `SELECT ${SESSION_ROW_COLUMNS} FROM sessions
+           WHERE (session_id = ? OR provider_session_id = ?)
+             AND session_id <> ?
+           LIMIT 1`
+        )
+        .get(providerSessionId, providerSessionId, sessionId) as SessionRow | undefined;
+
+      if (duplicate) {
+        db.prepare('DELETE FROM sessions WHERE session_id = ?').run(duplicate.session_id);
+        db.prepare(
+          `UPDATE sessions SET
+             provider_session_id = ?,
+             jsonl_path = COALESCE(jsonl_path, ?),
+             custom_name = COALESCE(custom_name, ?),
+             updated_at = CURRENT_TIMESTAMP
+           WHERE session_id = ?`
+        ).run(providerSessionId, duplicate.jsonl_path, duplicate.custom_name, sessionId);
+        return;
+      }
+
+      db.prepare(
+        `UPDATE sessions SET
+           provider_session_id = ?,
+           updated_at = CURRENT_TIMESTAMP
+         WHERE session_id = ?`
+      ).run(providerSessionId, sessionId);
+    });
+
+    merge();
+  },
+
   updateSessionCustomName(sessionId: string, customName: string): void {
     const db = getConnection();
     db.prepare(
@@ -85,17 +195,39 @@ export const sessionsDb = {
     ).run(customName, sessionId);
   },
 
-  getSessionById(sessionId: string): SessionMetadataLookupRow | null {
+  getSessionById(sessionId: string): SessionRow | null {
     const db = getConnection();
     const row = db
       .prepare(
-        `SELECT session_id, provider, project_path, jsonl_path, custom_name, isArchived, created_at, updated_at
+        `SELECT ${SESSION_ROW_COLUMNS}
          FROM sessions
          WHERE session_id = ?
          ORDER BY updated_at DESC
          LIMIT 1`
       )
-      .get(sessionId) as SessionMetadataLookupRow | undefined;
+      .get(sessionId) as SessionRow | undefined;
+
+    return row ?? null;
+  },
+
+  /**
+   * Resolves one session row through the provider-native id.
+   *
+   * The filesystem watcher only knows provider ids (they come from transcript
+   * file names), so it uses this lookup to translate disk artifacts back to
+   * the app-facing session row before broadcasting sidebar updates.
+   */
+  getSessionByProviderSessionId(providerSessionId: string): SessionRow | null {
+    const db = getConnection();
+    const row = db
+      .prepare(
+        `SELECT ${SESSION_ROW_COLUMNS}
+         FROM sessions
+         WHERE provider_session_id = ?
+         ORDER BY updated_at DESC
+         LIMIT 1`
+      )
+      .get(providerSessionId) as SessionRow | undefined;
 
     return row ?? null;
   },
@@ -104,7 +236,7 @@ export const sessionsDb = {
     const db = getConnection();
     return db
       .prepare(
-        `SELECT session_id, provider, project_path, jsonl_path, custom_name, isArchived, created_at, updated_at
+        `SELECT ${SESSION_ROW_COLUMNS}
          FROM sessions
          WHERE isArchived = 0`
       )
@@ -119,7 +251,7 @@ export const sessionsDb = {
     const db = getConnection();
     return db
       .prepare(
-        `SELECT session_id, provider, project_path, jsonl_path, custom_name, isArchived, created_at, updated_at
+        `SELECT ${SESSION_ROW_COLUMNS}
          FROM sessions
          WHERE isArchived = 1
          ORDER BY datetime(COALESCE(updated_at, created_at)) DESC, session_id DESC`
@@ -132,7 +264,7 @@ export const sessionsDb = {
     const normalizedProjectPath = normalizeProjectPath(projectPath);
     return db
       .prepare(
-        `SELECT session_id, provider, project_path, jsonl_path, custom_name, isArchived, created_at, updated_at
+        `SELECT ${SESSION_ROW_COLUMNS}
          FROM sessions
          WHERE project_path = ?
            AND isArchived = 0`
@@ -149,7 +281,7 @@ export const sessionsDb = {
     const normalizedProjectPath = normalizeProjectPath(projectPath);
     return db
       .prepare(
-        `SELECT session_id, provider, project_path, jsonl_path, custom_name, isArchived, created_at, updated_at
+        `SELECT ${SESSION_ROW_COLUMNS}
          FROM sessions
          WHERE project_path = ?`
       )
@@ -161,7 +293,7 @@ export const sessionsDb = {
     const normalizedProjectPath = normalizeProjectPath(projectPath);
     return db
       .prepare(
-        `SELECT session_id, provider, project_path, jsonl_path, custom_name, isArchived, created_at, updated_at
+        `SELECT ${SESSION_ROW_COLUMNS}
          FROM sessions
          WHERE project_path = ?
            AND isArchived = 0

server/modules/database/schema.ts

@@ -83,6 +83,12 @@ export const SESSIONS_TABLE_SCHEMA_SQL = `
 CREATE TABLE IF NOT EXISTS sessions (
     session_id TEXT NOT NULL,
     provider TEXT NOT NULL DEFAULT 'claude',
+    -- The session id used by the provider CLI/SDK on disk (JSONL file name,
+    -- store.db folder, sqlite row id, ...). \`session_id\` is the stable
+    -- app-facing id that the frontend uses for the whole session lifetime;
+    -- \`provider_session_id\` is filled in once the provider announces its own
+    -- id mid-run, or equals \`session_id\` for sessions discovered on disk.
+    provider_session_id TEXT,
     custom_name TEXT,
     project_path TEXT,
     jsonl_path TEXT,

server/modules/database/tests/sessions-provider-mapping.test.ts

@@ -0,0 +1,108 @@
+import assert from 'node:assert/strict';
+import { mkdtemp, rm } from 'node:fs/promises';
+import { tmpdir } from 'node:os';
+import path from 'node:path';
+import test from 'node:test';
+
+import { closeConnection } from '@/modules/database/connection.js';
+import { initializeDatabase } from '@/modules/database/init-db.js';
+import { sessionsDb } from '@/modules/database/repositories/sessions.db.js';
+
+async function withIsolatedDatabase(runTest: () => void | Promise<void>): Promise<void> {
+  const previousDatabasePath = process.env.DATABASE_PATH;
+  const tempDirectory = await mkdtemp(path.join(tmpdir(), 'sessions-mapping-'));
+  const databasePath = path.join(tempDirectory, 'auth.db');
+
+  closeConnection();
+  process.env.DATABASE_PATH = databasePath;
+  await initializeDatabase();
+
+  try {
+    await runTest();
+  } finally {
+    closeConnection();
+    if (previousDatabasePath === undefined) {
+      delete process.env.DATABASE_PATH;
+    } else {
+      process.env.DATABASE_PATH = previousDatabasePath;
+    }
+    await rm(tempDirectory, { recursive: true, force: true });
+  }
+}
+
+test('disk-discovered sessions are keyed by the provider id for both columns', async () => {
+  await withIsolatedDatabase(() => {
+    sessionsDb.createSession('provider-abc', 'claude', '/workspace/demo', 'From Disk');
+
+    const row = sessionsDb.getSessionById('provider-abc');
+    assert.equal(row?.session_id, 'provider-abc');
+    assert.equal(row?.provider_session_id, 'provider-abc');
+
+    const byProviderId = sessionsDb.getSessionByProviderSessionId('provider-abc');
+    assert.equal(byProviderId?.session_id, 'provider-abc');
+  });
+});
+
+test('app sessions get the provider id assigned without creating a duplicate row', async () => {
+  await withIsolatedDatabase(() => {
+    sessionsDb.createAppSession('app-id-1', 'claude', '/workspace/demo');
+    sessionsDb.assignProviderSessionId('app-id-1', 'provider-xyz');
+
+    // A later synchronizer pass that discovers the transcript on disk must
+    // update the app row in place instead of inserting a provider-keyed row.
+    const returnedId = sessionsDb.createSession(
+      'provider-xyz',
+      'claude',
+      '/workspace/demo',
+      'Synced Name',
+      undefined,
+      undefined,
+      '/fake/path/provider-xyz.jsonl',
+    );
+
+    assert.equal(returnedId, 'app-id-1');
+    assert.equal(sessionsDb.getAllSessions().length, 1);
+
+    const row = sessionsDb.getSessionById('app-id-1');
+    assert.equal(row?.provider_session_id, 'provider-xyz');
+    assert.equal(row?.jsonl_path, '/fake/path/provider-xyz.jsonl');
+  });
+});
+
+test('assignProviderSessionId merges a watcher-created duplicate into the app row', async () => {
+  await withIsolatedDatabase(() => {
+    sessionsDb.createAppSession('app-id-2', 'codex', '/workspace/demo');
+
+    // Simulate the race: the filesystem watcher indexed the provider
+    // transcript before the runtime announced its session id to the gateway.
+    sessionsDb.createSession(
+      'provider-race',
+      'codex',
+      '/workspace/demo',
+      'Watcher Name',
+      undefined,
+      undefined,
+      '/fake/provider-race.jsonl',
+    );
+    assert.equal(sessionsDb.getAllSessions().length, 2);
+
+    sessionsDb.assignProviderSessionId('app-id-2', 'provider-race');
+
+    const rows = sessionsDb.getAllSessions();
+    assert.equal(rows.length, 1);
+    assert.equal(rows[0]?.session_id, 'app-id-2');
+    assert.equal(rows[0]?.provider_session_id, 'provider-race');
+    // Transcript path and name from the duplicate are adopted.
+    assert.equal(rows[0]?.jsonl_path, '/fake/provider-race.jsonl');
+    assert.equal(rows[0]?.custom_name, 'Watcher Name');
+  });
+});
+
+test('legacy provider-keyed rows stay resolvable through both lookups', async () => {
+  await withIsolatedDatabase(() => {
+    sessionsDb.createSession('legacy-1', 'gemini', '/workspace/demo');
+
+    assert.equal(sessionsDb.getSessionById('legacy-1')?.provider, 'gemini');
+    assert.equal(sessionsDb.getSessionByProviderSessionId('legacy-1')?.session_id, 'legacy-1');
+  });
+});