diff --git a/.env.example b/.env.example
index 73cdb9f..1525bb2 100644
--- a/.env.example
+++ b/.env.example
@@ -69,6 +69,11 @@ WOODPECKER_DB_USER=woodpecker              # [CONFIG] Postgres user
 WOODPECKER_DB_HOST=127.0.0.1              # [CONFIG] Postgres host
 WOODPECKER_DB_NAME=woodpecker              # [CONFIG] Postgres database name
 
+# ── Chat OAuth (#708) ────────────────────────────────────────────────────
+CHAT_OAUTH_CLIENT_ID=                     # [SECRET] Chat OAuth2 client ID (auto-generated by init)
+CHAT_OAUTH_CLIENT_SECRET=                 # [SECRET] Chat OAuth2 client secret (auto-generated by init)
+DISINTO_CHAT_ALLOWED_USERS=               # [CONFIG] CSV of allowed usernames (disinto-admin always allowed)
+
 # ── Vault-only secrets (DO NOT put these in .env) ────────────────────────
 # These tokens grant access to external systems (GitHub, ClawHub, deploy targets).
 # They live ONLY in .env.vault.enc and are injected into the ephemeral runner
diff --git a/bin/disinto b/bin/disinto
index 34824f4..397a240 100755
--- a/bin/disinto
+++ b/bin/disinto
@@ -545,6 +545,12 @@ create_woodpecker_oauth() {
   _create_woodpecker_oauth_impl "$@"
 }
 
+# Create Chat OAuth2 app on Forgejo (implementation in lib/ci-setup.sh)
+create_chat_oauth() {
+  _load_ci_context
+  _create_chat_oauth_impl "$@"
+}
+
 # Generate WOODPECKER_TOKEN via Forgejo OAuth2 flow (implementation in lib/ci-setup.sh)
 generate_woodpecker_token() {
   _load_ci_context
@@ -958,6 +964,15 @@ p.write_text(text)
   _WP_REPO_ID=""
   create_woodpecker_oauth "$forge_url" "$forge_repo"
 
+  # Create OAuth2 app on Forgejo for disinto-chat (#708)
+  local chat_redirect_uri
+  if [ -n "${EDGE_TUNNEL_FQDN:-}" ]; then
+    chat_redirect_uri="https://${EDGE_TUNNEL_FQDN}/chat/oauth/callback"
+  else
+    chat_redirect_uri="http://localhost/chat/oauth/callback"
+  fi
+  create_chat_oauth "$chat_redirect_uri"
+
   # Generate WOODPECKER_AGENT_SECRET for server↔agent auth
   local env_file="${FACTORY_ROOT}/.env"
   if ! grep -q '^WOODPECKER_AGENT_SECRET=' "$env_file" 2>/dev/null; then
diff --git a/docker/chat/server.py b/docker/chat/server.py
index 485fce9..bbf3931 100644
--- a/docker/chat/server.py
+++ b/docker/chat/server.py
@@ -3,19 +3,32 @@
 disinto-chat server — minimal HTTP backend for Claude chat UI.
 
 Routes:
-    GET /          → serves index.html
-    GET /static/*  → serves static assets (htmx.min.js, etc.)
-    POST /chat     → spawns `claude --print` with user message, returns response
-    GET /ws        → reserved for future streaming upgrade (returns 501)
+    GET /chat/login          → 302 to Forgejo OAuth authorize
+    GET /chat/oauth/callback → exchange code for token, validate user, set session
+    GET /chat/               → serves index.html (session required)
+    GET /chat/static/*       → serves static assets (session required)
+    POST /chat               → spawns `claude --print` with user message (session required)
+    GET /ws                  → reserved for future streaming upgrade (returns 501)
+
+OAuth flow:
+    1. User hits any /chat/* route without a valid session cookie → 302 /chat/login
+    2. /chat/login redirects to Forgejo /login/oauth/authorize
+    3. Forgejo redirects back to /chat/oauth/callback with ?code=...&state=...
+    4. Server exchanges code for access token, fetches /api/v1/user
+    5. Asserts user is in allowlist, sets HttpOnly session cookie
+    6. Redirects to /chat/
 
 The claude binary is expected to be mounted from the host at /usr/local/bin/claude.
 """
 
+import json
 import os
+import secrets
 import subprocess
 import sys
+import time
 from http.server import HTTPServer, BaseHTTPRequestHandler
-from urllib.parse import urlparse, parse_qs
+from urllib.parse import urlparse, parse_qs, urlencode
 
 # Configuration
 HOST = os.environ.get("CHAT_HOST", "0.0.0.0")
@@ -24,6 +37,30 @@ UI_DIR = "/var/chat/ui"
 STATIC_DIR = os.path.join(UI_DIR, "static")
 CLAUDE_BIN = "/usr/local/bin/claude"
 
+# OAuth configuration
+FORGE_URL = os.environ.get("FORGE_URL", "http://localhost:3000")
+CHAT_OAUTH_CLIENT_ID = os.environ.get("CHAT_OAUTH_CLIENT_ID", "")
+CHAT_OAUTH_CLIENT_SECRET = os.environ.get("CHAT_OAUTH_CLIENT_SECRET", "")
+EDGE_TUNNEL_FQDN = os.environ.get("EDGE_TUNNEL_FQDN", "")
+
+# Allowed users — disinto-admin always allowed; CSV allowlist extends it
+_allowed_csv = os.environ.get("DISINTO_CHAT_ALLOWED_USERS", "")
+ALLOWED_USERS = {"disinto-admin"}
+if _allowed_csv:
+    ALLOWED_USERS.update(u.strip() for u in _allowed_csv.split(",") if u.strip())
+
+# Session cookie name
+SESSION_COOKIE = "disinto_chat_session"
+
+# Session TTL: 24 hours
+SESSION_TTL = 24 * 60 * 60
+
+# In-memory session store: token → {"user": str, "expires": float}
+_sessions = {}
+
+# Pending OAuth state tokens: state → expires (float)
+_oauth_states = {}
+
 # MIME types for static files
 MIME_TYPES = {
     ".html": "text/html; charset=utf-8",
@@ -37,14 +74,101 @@ MIME_TYPES = {
 }
 
 
+def _build_callback_uri():
+    """Build the OAuth callback URI based on tunnel configuration."""
+    if EDGE_TUNNEL_FQDN:
+        return f"https://{EDGE_TUNNEL_FQDN}/chat/oauth/callback"
+    return "http://localhost/chat/oauth/callback"
+
+
+def _session_cookie_flags():
+    """Return cookie flags appropriate for the deployment mode."""
+    flags = "HttpOnly; SameSite=Lax; Path=/chat"
+    if EDGE_TUNNEL_FQDN:
+        flags += "; Secure"
+    return flags
+
+
+def _validate_session(cookie_header):
+    """Check session cookie and return username if valid, else None."""
+    if not cookie_header:
+        return None
+    for part in cookie_header.split(";"):
+        part = part.strip()
+        if part.startswith(SESSION_COOKIE + "="):
+            token = part[len(SESSION_COOKIE) + 1:]
+            session = _sessions.get(token)
+            if session and session["expires"] > time.time():
+                return session["user"]
+            # Expired — clean up
+            _sessions.pop(token, None)
+            return None
+    return None
+
+
+def _gc_sessions():
+    """Remove expired sessions (called opportunistically)."""
+    now = time.time()
+    expired = [k for k, v in _sessions.items() if v["expires"] <= now]
+    for k in expired:
+        del _sessions[k]
+    expired_states = [k for k, v in _oauth_states.items() if v <= now]
+    for k in expired_states:
+        del _oauth_states[k]
+
+
+def _exchange_code_for_token(code):
+    """Exchange an authorization code for an access token via Forgejo."""
+    import urllib.request
+    import urllib.error
+
+    data = urlencode({
+        "grant_type": "authorization_code",
+        "code": code,
+        "client_id": CHAT_OAUTH_CLIENT_ID,
+        "client_secret": CHAT_OAUTH_CLIENT_SECRET,
+        "redirect_uri": _build_callback_uri(),
+    }).encode()
+
+    req = urllib.request.Request(
+        f"{FORGE_URL}/login/oauth/access_token",
+        data=data,
+        headers={"Accept": "application/json", "Content-Type": "application/x-www-form-urlencoded"},
+        method="POST",
+    )
+    try:
+        with urllib.request.urlopen(req, timeout=10) as resp:
+            return json.loads(resp.read().decode())
+    except (urllib.error.URLError, json.JSONDecodeError, OSError) as e:
+        print(f"OAuth token exchange failed: {e}", file=sys.stderr)
+        return None
+
+
+def _fetch_user(access_token):
+    """Fetch the authenticated user from Forgejo API."""
+    import urllib.request
+    import urllib.error
+
+    req = urllib.request.Request(
+        f"{FORGE_URL}/api/v1/user",
+        headers={"Authorization": f"token {access_token}", "Accept": "application/json"},
+    )
+    try:
+        with urllib.request.urlopen(req, timeout=10) as resp:
+            return json.loads(resp.read().decode())
+    except (urllib.error.URLError, json.JSONDecodeError, OSError) as e:
+        print(f"User fetch failed: {e}", file=sys.stderr)
+        return None
+
+
 class ChatHandler(BaseHTTPRequestHandler):
-    """HTTP request handler for disinto-chat."""
+    """HTTP request handler for disinto-chat with Forgejo OAuth."""
 
     def log_message(self, format, *args):
-        """Log to stdout instead of stderr."""
+        """Log to stderr."""
         print(f"[{self.log_date_time_string()}] {format % args}", file=sys.stderr)
 
-    def send_error(self, code, message=None):
+    def send_error_page(self, code, message=None):
         """Custom error response."""
         self.send_response(code)
         self.send_header("Content-Type", "text/plain; charset=utf-8")
@@ -52,47 +176,148 @@ class ChatHandler(BaseHTTPRequestHandler):
         if message:
             self.wfile.write(message.encode("utf-8"))
 
+    def _require_session(self):
+        """Check session; redirect to /chat/login if missing. Returns username or None."""
+        user = _validate_session(self.headers.get("Cookie"))
+        if user:
+            return user
+        self.send_response(302)
+        self.send_header("Location", "/chat/login")
+        self.end_headers()
+        return None
+
     def do_GET(self):
         """Handle GET requests."""
         parsed = urlparse(self.path)
         path = parsed.path
 
+        # OAuth routes (no session required)
+        if path == "/chat/login":
+            self.handle_login()
+            return
+
+        if path == "/chat/oauth/callback":
+            self.handle_oauth_callback(parsed.query)
+            return
+
         # Serve index.html at root
-        if path == "/" or path == "/chat":
+        if path in ("/", "/chat", "/chat/"):
+            if not self._require_session():
+                return
             self.serve_index()
             return
 
         # Serve static files
-        if path.startswith("/static/"):
+        if path.startswith("/chat/static/") or path.startswith("/static/"):
+            if not self._require_session():
+                return
             self.serve_static(path)
             return
 
         # Reserved WebSocket endpoint (future use)
         if path == "/ws" or path.startswith("/ws"):
-            self.send_error(501, "WebSocket upgrade not yet implemented")
+            self.send_error_page(501, "WebSocket upgrade not yet implemented")
             return
 
         # 404 for unknown paths
-        self.send_error(404, "Not found")
+        self.send_error_page(404, "Not found")
 
     def do_POST(self):
         """Handle POST requests."""
         parsed = urlparse(self.path)
         path = parsed.path
 
-        # Chat endpoint
-        if path == "/chat" or path == "/chat/":
+        # Chat endpoint (session required)
+        if path in ("/chat", "/chat/"):
+            if not self._require_session():
+                return
             self.handle_chat()
             return
 
         # 404 for unknown paths
-        self.send_error(404, "Not found")
+        self.send_error_page(404, "Not found")
+
+    def handle_login(self):
+        """Redirect to Forgejo OAuth authorize endpoint."""
+        _gc_sessions()
+
+        if not CHAT_OAUTH_CLIENT_ID:
+            self.send_error_page(500, "Chat OAuth not configured (CHAT_OAUTH_CLIENT_ID missing)")
+            return
+
+        state = secrets.token_urlsafe(32)
+        _oauth_states[state] = time.time() + 600  # 10 min validity
+
+        params = urlencode({
+            "client_id": CHAT_OAUTH_CLIENT_ID,
+            "redirect_uri": _build_callback_uri(),
+            "response_type": "code",
+            "state": state,
+        })
+        self.send_response(302)
+        self.send_header("Location", f"{FORGE_URL}/login/oauth/authorize?{params}")
+        self.end_headers()
+
+    def handle_oauth_callback(self, query_string):
+        """Exchange authorization code for token, validate user, set session."""
+        params = parse_qs(query_string)
+        code = params.get("code", [""])[0]
+        state = params.get("state", [""])[0]
+
+        # Validate state
+        expected_expiry = _oauth_states.pop(state, None) if state else None
+        if not expected_expiry or expected_expiry < time.time():
+            self.send_error_page(400, "Invalid or expired OAuth state")
+            return
+
+        if not code:
+            self.send_error_page(400, "Missing authorization code")
+            return
+
+        # Exchange code for access token
+        token_resp = _exchange_code_for_token(code)
+        if not token_resp or "access_token" not in token_resp:
+            self.send_error_page(502, "Failed to obtain access token from Forgejo")
+            return
+
+        access_token = token_resp["access_token"]
+
+        # Fetch user info
+        user_info = _fetch_user(access_token)
+        if not user_info or "login" not in user_info:
+            self.send_error_page(502, "Failed to fetch user info from Forgejo")
+            return
+
+        username = user_info["login"]
+
+        # Check allowlist
+        if username not in ALLOWED_USERS:
+            self.send_response(403)
+            self.send_header("Content-Type", "text/plain; charset=utf-8")
+            self.end_headers()
+            self.wfile.write(
+                f"Not authorised: user '{username}' is not in the allowed users list.\n".encode()
+            )
+            return
+
+        # Create session
+        session_token = secrets.token_urlsafe(48)
+        _sessions[session_token] = {
+            "user": username,
+            "expires": time.time() + SESSION_TTL,
+        }
+
+        cookie_flags = _session_cookie_flags()
+        self.send_response(302)
+        self.send_header("Set-Cookie", f"{SESSION_COOKIE}={session_token}; {cookie_flags}")
+        self.send_header("Location", "/chat/")
+        self.end_headers()
 
     def serve_index(self):
         """Serve the main index.html file."""
         index_path = os.path.join(UI_DIR, "index.html")
         if not os.path.exists(index_path):
-            self.send_error(500, "UI not found")
+            self.send_error_page(500, "UI not found")
             return
 
         try:
@@ -104,19 +329,23 @@ class ChatHandler(BaseHTTPRequestHandler):
             self.end_headers()
             self.wfile.write(content.encode("utf-8"))
         except IOError as e:
-            self.send_error(500, f"Error reading index.html: {e}")
+            self.send_error_page(500, f"Error reading index.html: {e}")
 
     def serve_static(self, path):
         """Serve static files from the static directory."""
-        # Sanitize path to prevent directory traversal
-        relative_path = path[len("/static/"):]
+        # Strip /chat/static/ or /static/ prefix
+        if path.startswith("/chat/static/"):
+            relative_path = path[len("/chat/static/"):]
+        else:
+            relative_path = path[len("/static/"):]
+
         if ".." in relative_path or relative_path.startswith("/"):
-            self.send_error(403, "Forbidden")
+            self.send_error_page(403, "Forbidden")
             return
 
         file_path = os.path.join(STATIC_DIR, relative_path)
         if not os.path.exists(file_path):
-            self.send_error(404, "Not found")
+            self.send_error_page(404, "Not found")
             return
 
         # Determine MIME type
@@ -132,7 +361,7 @@ class ChatHandler(BaseHTTPRequestHandler):
             self.end_headers()
             self.wfile.write(content)
         except IOError as e:
-            self.send_error(500, f"Error reading file: {e}")
+            self.send_error_page(500, f"Error reading file: {e}")
 
     def handle_chat(self):
         """
@@ -142,7 +371,7 @@ class ChatHandler(BaseHTTPRequestHandler):
         # Read request body
         content_length = int(self.headers.get("Content-Length", 0))
         if content_length == 0:
-            self.send_error(400, "No message provided")
+            self.send_error_page(400, "No message provided")
             return
 
         body = self.rfile.read(content_length)
@@ -152,16 +381,16 @@ class ChatHandler(BaseHTTPRequestHandler):
             params = parse_qs(body_str)
             message = params.get("message", [""])[0]
         except (UnicodeDecodeError, KeyError):
-            self.send_error(400, "Invalid message format")
+            self.send_error_page(400, "Invalid message format")
             return
 
         if not message:
-            self.send_error(400, "Empty message")
+            self.send_error_page(400, "Empty message")
             return
 
         # Validate Claude binary exists
         if not os.path.exists(CLAUDE_BIN):
-            self.send_error(500, "Claude CLI not found")
+            self.send_error_page(500, "Claude CLI not found")
             return
 
         try:
@@ -186,7 +415,7 @@ class ChatHandler(BaseHTTPRequestHandler):
 
             # Check for errors
             if proc.returncode != 0:
-                self.send_error(500, f"Claude CLI failed with exit code {proc.returncode}")
+                self.send_error_page(500, f"Claude CLI failed with exit code {proc.returncode}")
                 return
             self.send_response(200)
             self.send_header("Content-Type", "text/plain; charset=utf-8")
@@ -195,9 +424,9 @@ class ChatHandler(BaseHTTPRequestHandler):
             self.wfile.write(response.encode("utf-8"))
 
         except FileNotFoundError:
-            self.send_error(500, "Claude CLI not found")
+            self.send_error_page(500, "Claude CLI not found")
         except Exception as e:
-            self.send_error(500, f"Error: {e}")
+            self.send_error_page(500, f"Error: {e}")
 
 
 def main():
@@ -205,7 +434,12 @@ def main():
     server_address = (HOST, PORT)
     httpd = HTTPServer(server_address, ChatHandler)
     print(f"Starting disinto-chat server on {HOST}:{PORT}", file=sys.stderr)
-    print(f"UI available at http://localhost:{PORT}/", file=sys.stderr)
+    print(f"UI available at http://localhost:{PORT}/chat/", file=sys.stderr)
+    if CHAT_OAUTH_CLIENT_ID:
+        print(f"OAuth enabled (client_id={CHAT_OAUTH_CLIENT_ID[:8]}...)", file=sys.stderr)
+        print(f"Allowed users: {', '.join(sorted(ALLOWED_USERS))}", file=sys.stderr)
+    else:
+        print("WARNING: CHAT_OAUTH_CLIENT_ID not set — OAuth disabled", file=sys.stderr)
     httpd.serve_forever()
 
 
diff --git a/lib/AGENTS.md b/lib/AGENTS.md
index 01869e2..bfc7435 100644
--- a/lib/AGENTS.md
+++ b/lib/AGENTS.md
@@ -29,7 +29,7 @@ sourced as needed.
 | `lib/forge-push.sh` | `push_to_forge()` — pushes a local clone to the Forgejo remote and verifies the push. `_assert_forge_push_globals()` validates required env vars before use. Requires `FORGE_URL`, `FORGE_PASS`, `FACTORY_ROOT`, `PRIMARY_BRANCH`. **Auth**: uses `FORGE_PASS` (bot password) for git HTTP push — Forgejo 11.x rejects API tokens for `git push` (#361). | bin/disinto (init) |
 | `lib/git-creds.sh` | Shared git credential helper configuration. `configure_git_creds([HOME_DIR] [RUN_AS_CMD])` — writes a static credential helper script and configures git globally to use password-based HTTP auth (Forgejo 11.x rejects API tokens for `git push`, #361). `repair_baked_cred_urls([--as RUN_AS_CMD] DIR ...)` — rewrites any git remote URLs that have credentials baked in to use clean URLs instead; uses `safe.directory` bypass for root-owned repos (#671). Requires `FORGE_PASS`, `FORGE_URL`, `FORGE_TOKEN`. | entrypoints (agents, edge) |
 | `lib/ops-setup.sh` | `setup_ops_repo()` — creates ops repo on Forgejo if it doesn't exist, configures bot collaborators, clones/initializes ops repo locally, seeds directory structure (vault, knowledge, evidence, sprints). Evidence subdirectories seeded: engagement/, red-team/, holdout/, evolution/, user-test/. Also seeds sprints/ for architect output. Exports `_ACTUAL_OPS_SLUG`. `migrate_ops_repo(ops_root, [primary_branch])` — idempotent migration helper that seeds missing directories and .gitkeep files on existing ops repos (pre-#407 deployments). | bin/disinto (init) |
-| `lib/ci-setup.sh` | `_install_cron_impl()` — installs crontab entries for bare-metal deployments (compose mode uses polling loop instead). `_create_woodpecker_oauth_impl()` — creates OAuth2 app on Forgejo for Woodpecker. `_generate_woodpecker_token_impl()` — auto-generates WOODPECKER_TOKEN via OAuth2 flow. `_activate_woodpecker_repo_impl()` — activates repo in Woodpecker. All gated by `_load_ci_context()` which validates required env vars. | bin/disinto (init) |
+| `lib/ci-setup.sh` | `_install_cron_impl()` — installs crontab entries for bare-metal deployments (compose mode uses polling loop instead). `_create_forgejo_oauth_app()` — generic helper to create an OAuth2 app on Forgejo (shared by Woodpecker and chat). `_create_woodpecker_oauth_impl()` — creates Woodpecker OAuth2 app (thin wrapper). `_create_chat_oauth_impl()` — creates disinto-chat OAuth2 app, writes `CHAT_OAUTH_CLIENT_ID`/`CHAT_OAUTH_CLIENT_SECRET` to `.env` (#708). `_generate_woodpecker_token_impl()` — auto-generates WOODPECKER_TOKEN via OAuth2 flow. `_activate_woodpecker_repo_impl()` — activates repo in Woodpecker. All gated by `_load_ci_context()` which validates required env vars. | bin/disinto (init) |
 | `lib/generators.sh` | Template generation for `disinto init`: `generate_compose()` — docker-compose.yml (uses `codeberg.org/forgejo/forgejo:11.0` tag; adds `security_opt: [apparmor:unconfined]` to all services for rootless container compatibility; Forgejo includes a healthcheck so dependent services use `condition: service_healthy` — fixes cold-start races, #665; adds `chat` service block with isolated `chat-config` named volume; all `depends_on` now use `condition: service_healthy/started` instead of bare service names), `generate_caddyfile()` — Caddyfile (routes: `/forge/*` → forgejo:3000, `/woodpecker/*` → woodpecker:8000, `/staging/*` → staging:80, `/chat/*` → chat:8080; root `/` redirects to `/forge/`), `generate_staging_index()` — staging index, `generate_deploy_pipelines()` — Woodpecker deployment pipeline configs. Requires `FACTORY_ROOT`, `PROJECT_NAME`, `PRIMARY_BRANCH`. | bin/disinto (init) |
 | `lib/hire-agent.sh` | `disinto_hire_an_agent()` — user creation, `.profile` repo setup, formula copying, branch protection, and state marker creation for hiring a new agent. Requires `FORGE_URL`, `FORGE_TOKEN`, `FACTORY_ROOT`, `PROJECT_NAME`. Extracted from `bin/disinto`. | bin/disinto (hire) |
 | `lib/release.sh` | `disinto_release()` — vault TOML creation, branch setup on ops repo, PR creation, and auto-merge request for a versioned release. `_assert_release_globals()` validates required env vars. Requires `FORGE_URL`, `FORGE_TOKEN`, `FORGE_OPS_REPO`, `FACTORY_ROOT`, `PRIMARY_BRANCH`. Extracted from `bin/disinto`. | bin/disinto (release) |
diff --git a/lib/ci-setup.sh b/lib/ci-setup.sh
index 0386c37..319e83e 100644
--- a/lib/ci-setup.sh
+++ b/lib/ci-setup.sh
@@ -4,7 +4,9 @@
 #
 # Internal functions (called via _load_ci_context + _*_impl):
 #   _install_cron_impl()              - Install crontab entries (bare-metal only; compose uses polling loop)
+#   _create_forgejo_oauth_app()       - Generic: create an OAuth2 app on Forgejo (shared helper)
 #   _create_woodpecker_oauth_impl()   - Create OAuth2 app on Forgejo for Woodpecker
+#   _create_chat_oauth_impl()         - Create OAuth2 app on Forgejo for disinto-chat
 #   _generate_woodpecker_token_impl() - Auto-generate WOODPECKER_TOKEN via OAuth2 flow
 #   _activate_woodpecker_repo_impl()  - Activate repo in Woodpecker
 #
@@ -90,6 +92,54 @@ _install_cron_impl() {
   fi
 }
 
+# Create an OAuth2 application on Forgejo.
+# Generic helper used by both Woodpecker and chat OAuth setup.
+# Sets _OAUTH_CLIENT_ID and _OAUTH_CLIENT_SECRET on success.
+# Usage: _create_forgejo_oauth_app <app_name> <redirect_uri>
+_create_forgejo_oauth_app() {
+  local oauth2_name="$1"
+  local redirect_uri="$2"
+  local forge_url="${FORGE_URL}"
+
+  _OAUTH_CLIENT_ID=""
+  _OAUTH_CLIENT_SECRET=""
+
+  local existing_app
+  existing_app=$(curl -sf \
+    -H "Authorization: token ${FORGE_TOKEN}" \
+    "${forge_url}/api/v1/user/applications/oauth2" 2>/dev/null \
+    | jq -r --arg name "$oauth2_name" '.[] | select(.name == $name) | .client_id // empty' 2>/dev/null) || true
+
+  if [ -n "$existing_app" ]; then
+    echo "OAuth2:  ${oauth2_name} (already exists, client_id=${existing_app})"
+    _OAUTH_CLIENT_ID="$existing_app"
+    return 0
+  fi
+
+  local oauth2_resp
+  oauth2_resp=$(curl -sf -X POST \
+    -H "Authorization: token ${FORGE_TOKEN}" \
+    -H "Content-Type: application/json" \
+    "${forge_url}/api/v1/user/applications/oauth2" \
+    -d "{\"name\":\"${oauth2_name}\",\"redirect_uris\":[\"${redirect_uri}\"],\"confidential_client\":true}" \
+    2>/dev/null) || oauth2_resp=""
+
+  if [ -z "$oauth2_resp" ]; then
+    echo "Warning: failed to create OAuth2 app '${oauth2_name}' on Forgejo" >&2
+    return 1
+  fi
+
+  _OAUTH_CLIENT_ID=$(printf '%s' "$oauth2_resp" | jq -r '.client_id // empty')
+  _OAUTH_CLIENT_SECRET=$(printf '%s' "$oauth2_resp" | jq -r '.client_secret // empty')
+
+  if [ -z "$_OAUTH_CLIENT_ID" ]; then
+    echo "Warning: OAuth2 app creation returned no client_id" >&2
+    return 1
+  fi
+
+  echo "OAuth2:  ${oauth2_name} created (client_id=${_OAUTH_CLIENT_ID})"
+}
+
 # Set up Woodpecker CI to use Forgejo as its forge backend.
 # Creates an OAuth2 app on Forgejo for Woodpecker, activates the repo.
 # Usage: create_woodpecker_oauth <forge_url> <repo_slug>
@@ -100,44 +150,9 @@ _create_woodpecker_oauth_impl() {
   echo ""
   echo "── Woodpecker OAuth2 setup ────────────────────────────"
 
-  # Create OAuth2 application on Forgejo for Woodpecker
-  local oauth2_name="woodpecker-ci"
-  local redirect_uri="http://localhost:8000/authorize"
-  local existing_app client_id client_secret
-
-  # Check if OAuth2 app already exists
-  existing_app=$(curl -sf \
-    -H "Authorization: token ${FORGE_TOKEN}" \
-    "${forge_url}/api/v1/user/applications/oauth2" 2>/dev/null \
-    | jq -r --arg name "$oauth2_name" '.[] | select(.name == $name) | .client_id // empty' 2>/dev/null) || true
-
-  if [ -n "$existing_app" ]; then
-    echo "OAuth2:  ${oauth2_name} (already exists, client_id=${existing_app})"
-    client_id="$existing_app"
-  else
-    local oauth2_resp
-    oauth2_resp=$(curl -sf -X POST \
-      -H "Authorization: token ${FORGE_TOKEN}" \
-      -H "Content-Type: application/json" \
-      "${forge_url}/api/v1/user/applications/oauth2" \
-      -d "{\"name\":\"${oauth2_name}\",\"redirect_uris\":[\"${redirect_uri}\"],\"confidential_client\":true}" \
-      2>/dev/null) || oauth2_resp=""
-
-    if [ -z "$oauth2_resp" ]; then
-      echo "Warning: failed to create OAuth2 app on Forgejo" >&2
-      return
-    fi
-
-    client_id=$(printf '%s' "$oauth2_resp" | jq -r '.client_id // empty')
-    client_secret=$(printf '%s' "$oauth2_resp" | jq -r '.client_secret // empty')
-
-    if [ -z "$client_id" ]; then
-      echo "Warning: OAuth2 app creation returned no client_id" >&2
-      return
-    fi
-
-    echo "OAuth2:  ${oauth2_name} created (client_id=${client_id})"
-  fi
+  _create_forgejo_oauth_app "woodpecker-ci" "http://localhost:8000/authorize" || return 0
+  local client_id="${_OAUTH_CLIENT_ID}"
+  local client_secret="${_OAUTH_CLIENT_SECRET}"
 
   # Store Woodpecker forge config in .env
   # WP_FORGEJO_CLIENT/SECRET match the docker-compose.yml variable references
@@ -166,6 +181,39 @@ _create_woodpecker_oauth_impl() {
   echo "Config:  Woodpecker forge vars written to .env"
 }
 
+# Create OAuth2 app on Forgejo for disinto-chat.
+# Writes CHAT_OAUTH_CLIENT_ID / CHAT_OAUTH_CLIENT_SECRET to .env.
+# Usage: _create_chat_oauth_impl <redirect_uri>
+_create_chat_oauth_impl() {
+  local redirect_uri="$1"
+
+  echo ""
+  echo "── Chat OAuth2 setup ──────────────────────────────────"
+
+  _create_forgejo_oauth_app "disinto-chat" "$redirect_uri" || return 0
+  local client_id="${_OAUTH_CLIENT_ID}"
+  local client_secret="${_OAUTH_CLIENT_SECRET}"
+
+  local env_file="${FACTORY_ROOT}/.env"
+  local chat_vars=()
+  if [ -n "${client_id:-}" ]; then
+    chat_vars+=("CHAT_OAUTH_CLIENT_ID=${client_id}")
+  fi
+  if [ -n "${client_secret:-}" ]; then
+    chat_vars+=("CHAT_OAUTH_CLIENT_SECRET=${client_secret}")
+  fi
+
+  for var_line in "${chat_vars[@]}"; do
+    local var_name="${var_line%%=*}"
+    if grep -q "^${var_name}=" "$env_file" 2>/dev/null; then
+      sed -i "s|^${var_name}=.*|${var_line}|" "$env_file"
+    else
+      printf '%s\n' "$var_line" >> "$env_file"
+    fi
+  done
+  echo "Config:  Chat OAuth vars written to .env"
+}
+
 # Auto-generate WOODPECKER_TOKEN by driving the Forgejo OAuth2 login flow.
 # Requires _FORGE_ADMIN_PASS (set by setup_forge when admin user was just created).
 # Called after compose stack is up, before activate_woodpecker_repo.
diff --git a/lib/generators.sh b/lib/generators.sh
index e876272..33b1c1d 100644
--- a/lib/generators.sh
+++ b/lib/generators.sh
@@ -501,7 +501,12 @@ services:
     environment:
       CHAT_HOST: "0.0.0.0"
       CHAT_PORT: "8080"
-      # Point Claude to separate identity directory
+      FORGE_URL: http://forgejo:3000
+      CHAT_OAUTH_CLIENT_ID: ${CHAT_OAUTH_CLIENT_ID:-}
+      CHAT_OAUTH_CLIENT_SECRET: ${CHAT_OAUTH_CLIENT_SECRET:-}
+      EDGE_TUNNEL_FQDN: ${EDGE_TUNNEL_FQDN:-}
+      DISINTO_CHAT_ALLOWED_USERS: ${DISINTO_CHAT_ALLOWED_USERS:-}
+      # Point Claude to separate identity directory (#707)
       CLAUDE_CONFIG_DIR: /home/chat/.claude-chat/config
       CLAUDE_CREDENTIALS_DIR: /home/chat/.claude-chat/config/credentials
     networks: