A host can now contribute tools for one session through McpAttachOptions.dynamicTools, consulted once per attach() with that session's ctx. It belongs here rather than in the host calling server.registerTool() itself, because attach() is where the onInvoke seam fires. Anything registered outside it is invisible to the tool-call audit trail, and handlers that run as the calling user are the last thing that should sit in an audit blind spot. The source is synchronous: attach() runs inside the initialize request, so an awaited source would put a third party's round trip in front of every session creation. Two properties carry the weight, both security ones: - Names are reserved against every registered entry, not against what this session was granted. Reserving against the session would mean a token scoped to trips:read has no create_trip attached, so a contributed tool could take that name for exactly the callers holding no scope for it. - Nothing a contributor does can make attach() throw. Hosts call it outside their request try block, so an escape is a 500 on every initialize and one bad contributor takes MCP down instance-wide. The source is contained once, each entry again. Both live throw sites are covered: the SDK duplicate-name throw, and the policy-less declarative access throw that registered entries only avoid because validate() pre-checks them at boot. ToolOptions.inputSchema widens to ZodRawShape | McpZodSchema. The SDK has accepted either since it normalises both to one object schema, and a whole schema is what lets a host advertise one it did not author (via .meta()) without converting it to Zod first. The arms are disjoint, so nothing else moves; one test cast in decorators.test.ts records which arm that decorator declared. DYNTOOL-001 to DYNTOOL-014.
A self-hosted, real-time collaborative travel planner — with maps, budgets, packing lists, a journal, and AI built in.
What you get
See all features
Most of what follows is an addon an admin switches on or off. Lists, Costs, Documents, Collab, Vacay and Atlas ship on; Journey, Collections, MCP, AI Parsing and AirTrail ship off and are marked below.
🧭 Planning
|
🧳 Bookings and money
|
👥 Collaboration
📔 Journal, Atlas and Vacay
|
🧩 Plugins
🤖 AI and MCP
|
📱 Mobile and offline
|
⚙️ Admin, accounts and security
|
AI usage
We use LLM-assisted coding tools across parts of this codebase. Nothing ships that a maintainer has not read and understood: every change goes through a pull request, is reviewed and tested, and has a human who can answer for it. "The AI wrote that" is not an answer any of us would accept from ourselves.
See How we use AI in TREK for the details.
Get started in 30 seconds
ENCRYPTION_KEY=$(openssl rand -hex 32) docker run -d -p 3000:3000 \
-e ENCRYPTION_KEY=$ENCRYPTION_KEY \
-v ./data:/app/data -v ./uploads:/app/uploads mauriceboe/trek
Open http://localhost:3000. On first boot TREK seeds an admin account — if you set ADMIN_EMAIL/ADMIN_PASSWORD those are used, otherwise the credentials are printed to the container log (docker logs trek).
Tech stack
Real-time sync via WebSocket (ws). Backend on NestJS 11. State with Zustand. Auth via JWT + OAuth 2.1 + OIDC + Passkeys (WebAuthn) + TOTP MFA. Weather via Open-Meteo (no key required). Maps with Leaflet and Mapbox GL.
Docker Compose (production)
The repository ships a ready-to-use docker-compose.yml
with secure defaults and every option documented inline. Download it, then:
docker compose up -d
See Install with Docker Compose for the full walkthrough.
Helm (Kubernetes)
helm repo add trek https://chart.liketrek.com
helm repo update
helm install trek trek/trek
See charts/README.md for values.
Install as App (PWA)
TREK works as a Progressive Web App — no App Store needed.
- Open TREK in the browser (HTTPS required)
- iOS: Share ▸ Add to Home Screen
- Android: Menu ▸ Install app (or Add to Home Screen)
TREK then launches fullscreen with its own icon, just like a native app.
Updating
See Updating — Docker Compose, Docker run, Helm, Portainer, Unraid and Proxmox, plus the encryption-key note.
Reverse Proxy
For production, put TREK behind a TLS-terminating reverse proxy. TREK uses WebSockets for real-time sync, so the proxy must support WebSocket upgrades on /ws.
If you use the MCP addon, the proxy must also pass the Mcp-Session-Id header through in both directions on /mcp — Nginx and Caddy do this by default, but a proxy that strips it makes every tool call open a new session instead of reusing one. See the Reverse Proxy wiki page for details.
Nginx
server {
listen 80;
server_name trek.yourdomain.com;
return 301 https://$host$request_uri;
}
server {
listen 443 ssl http2;
server_name trek.yourdomain.com;
ssl_certificate /etc/ssl/fullchain.pem;
ssl_certificate_key /etc/ssl/privkey.pem;
# 500 MB covers backup-restore uploads (capped at 500 MB server-side).
client_max_body_size 500m;
location / {
proxy_pass http://localhost:3000;
proxy_http_version 1.1;
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Proto $scheme;
}
location /ws {
proxy_pass http://localhost:3000;
proxy_http_version 1.1;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection "upgrade";
proxy_set_header Host $host;
proxy_read_timeout 86400;
}
# Only needed if you use the MCP addon. Responses are Server-Sent Events,
# so buffering must be off or tool results arrive late.
location /mcp {
proxy_pass http://localhost:3000;
proxy_http_version 1.1;
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Proto $scheme;
proxy_buffering off;
proxy_read_timeout 3600s;
}
}
Caddy
trek.yourdomain.com {
reverse_proxy localhost:3000
}
Caddy handles TLS and WebSockets automatically.
Environment variables
Every variable, its default and what it does: see Environment Variables.
Star History
Data sources
The Atlas map's country and sub-national (province/county) boundaries come from geoBoundaries (Runfola et al., 2020), licensed CC BY 4.0. See NOTICE.md for full third-party attributions.
License
TREK is AGPL v3. Self-host freely for personal or internal company use. If you modify and offer TREK as a network service to third parties, your modifications must be open-sourced under the same licence.



