chat: read the /chat session list from Claude's own transcript store

First slice of making Claude's session store the source of truth. Adds a reader
(api/chat/claude-sessions.ts) that lists sessions straight from Claude's JSONL
transcripts under $HOME/.claude/projects/<cwd-slug>/, plus GET /chat/sessions
over a dedicated per-user claude_sessions working directory. No bookkeeping
layer — Claude's files are authoritative. Verified against real transcripts.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/servers/api/chat/chat.ts

@@ -0,0 +1,12 @@
+import { createRouter } from '../../create-router';
+import { getClaudeSessionsCwd, listClaudeSessions } from './claude-sessions';
+
+export const chatRouter = createRouter();
+
+// GET /chat/sessions — the /chat route's conversations, read straight from Claude's own transcript
+// store for the dedicated claude_sessions working directory (Claude is the source of truth).
+chatRouter.get('/sessions', (ctx) => {
+  const email = ctx.get('user').email;
+  const sessions = listClaudeSessions(email, getClaudeSessionsCwd(email));
+  return ctx.json({ sessions });
+});

src/servers/api/chat/claude-sessions.ts

@@ -0,0 +1,110 @@
+import { readdirSync, readFileSync, existsSync, statSync } from 'node:fs';
+import { join } from 'node:path';
+import { DATA_PATH } from '../../data-path';
+
+// ── Claude session store (source of truth) ──
+// The `claude` CLI persists every session as a JSONL transcript at
+//   $HOME/.claude/projects/<slug>/<session-uuid>.jsonl
+// where <slug> is the working directory with every non-alphanumeric char replaced by '-'.
+// A user's claude process runs with HOME = DATA_PATH/<email>/home (see sidecar/claude/user-instance.ts),
+// so we read transcripts from there. We never maintain our own copy — Claude's files are authoritative.
+
+/** Dedicated working directory for /chat sessions, so they form their own Claude "project" group. */
+export const getClaudeSessionsCwd = (email: string): string => join(DATA_PATH, email, 'claude_sessions');
+
+const claudeProjectsDir = (email: string): string => join(DATA_PATH, email, 'home', '.claude', 'projects');
+
+/** Claude's folder name for a working directory. */
+export const projectSlug = (cwd: string): string => cwd.replace(/[^a-zA-Z0-9]/g, '-');
+
+export type ClaudeSessionSummary = {
+  id: string; // session uuid (= transcript filename)
+  title: string; // first human message, trimmed
+  cwd: string;
+  createdAt: string; // ISO, first entry
+  updatedAt: string; // ISO, last entry
+  messageCount: number; // human + assistant turns
+};
+
+/** Pull the plain text out of a transcript entry's `message.content` (string or content-block array). */
+function entryText(message: unknown): string {
+  if (!message || typeof message !== 'object') return '';
+  const content = (message as { content?: unknown }).content;
+  if (typeof content === 'string') return content;
+  if (Array.isArray(content)) {
+    return content
+      .map((block) => (block && typeof block === 'object' && (block as { type?: string }).type === 'text' ? (block as { text?: string }).text ?? '' : ''))
+      .join('')
+      .trim();
+  }
+  return '';
+}
+
+type Entry = {
+  type?: string;
+  timestamp?: string;
+  sessionId?: string;
+  cwd?: string;
+  message?: { role?: string; content?: unknown };
+  isMeta?: boolean;
+};
+
+function summarizeTranscript(filePath: string, id: string): ClaudeSessionSummary | null {
+  let raw: string;
+  try {
+    raw = readFileSync(filePath, 'utf-8');
+  } catch {
+    return null;
+  }
+
+  let title = '';
+  let cwd = '';
+  let firstTs = '';
+  let lastTs = '';
+  let messageCount = 0;
+
+  for (const line of raw.split('\n')) {
+    if (!line.trim()) continue;
+    let entry: Entry;
+    try {
+      entry = JSON.parse(line) as Entry;
+    } catch {
+      continue;
+    }
+    if (entry.cwd && !cwd) cwd = entry.cwd;
+    if (entry.timestamp) {
+      if (!firstTs) firstTs = entry.timestamp;
+      lastTs = entry.timestamp;
+    }
+    if (entry.type === 'user' || entry.type === 'assistant') {
+      messageCount += 1;
+      if (!title && entry.type === 'user' && !entry.isMeta) {
+        title = entryText(entry.message).split('\n')[0]!.trim();
+      }
+    }
+  }
+
+  const mtime = statSync(filePath).mtime.toISOString();
+  return {
+    id,
+    title: title || '(untitled)',
+    cwd,
+    createdAt: firstTs || mtime,
+    updatedAt: lastTs || mtime,
+    messageCount,
+  };
+}
+
+/** List sessions Claude has stored for a given working directory, newest first. */
+export function listClaudeSessions(email: string, cwd: string): ClaudeSessionSummary[] {
+  const dir = join(claudeProjectsDir(email), projectSlug(cwd));
+  if (!existsSync(dir)) return [];
+
+  const sessions: ClaudeSessionSummary[] = [];
+  for (const file of readdirSync(dir)) {
+    if (!file.endsWith('.jsonl')) continue;
+    const summary = summarizeTranscript(join(dir, file), file.replace(/\.jsonl$/, ''));
+    if (summary) sessions.push(summary);
+  }
+  return sessions.sort((a, b) => b.updatedAt.localeCompare(a.updatedAt));
+}

src/servers/hono.ts

@@ -31,6 +31,7 @@ import { desktopRouter } from './api/desktop/rest';
 import { appsRouter, appServeRouter } from './api/apps';
 import { bugReportRouter } from './api/bug-report/bug-report';
 import { savedSessionsRouter } from './api/saved-sessions/saved-sessions';
+import { chatRouter } from './api/chat/chat';
 import { pipelineJobsRouter } from './api/tasks/pipeline-jobs-routes';
 import { broadcastPanelRefresh } from './api/terminal/websocket';
 import { CustomError } from './custom-errors';
@@ -103,6 +104,7 @@ protectedRouter.route('/browser', browserRouter);
 protectedRouter.route('/apps', appsRouter);
 protectedRouter.route('/bug-report', bugReportRouter);
 protectedRouter.route('/saved-sessions', savedSessionsRouter);
+protectedRouter.route('/chat', chatRouter);
 protectedRouter.route('/pipeline-jobs', pipelineJobsRouter);
 protectedRouter.route('/jobs', pipelineJobsRouter); // unified jobs API (script + pipeline); /pipeline-jobs kept for the existing UI
 desktopRouter.use(superAdminMiddleware);