# Fastn MCP Server
**Give your AI agents and apps instant, secure access to 250+ enterprise systems.**
Fastn MCP Server is a production-ready [Model Context Protocol (MCP)](https://modelcontextprotocol.io/) gateway that connects AI agents and apps to Slack, Jira, GitHub, Salesforce, HubSpot, Postgres, and 200+ more services — with fully managed auth, governed access, and sub-second execution.
Built on the [Fastn SDK](https://github.com/fastnai/fastn-sdk), this server exposes MCP tools that any compatible AI platform can use out of the box.
## Why Fastn MCP Server?
| Feature | Description |
|---------|-------------|
| **250+ Connectors** | Slack, Jira, GitHub, Salesforce, HubSpot, Postgres, Stripe, Notion, Linear, and more |
| **MCP Native** | Works with Claude Desktop, Cursor, Lovable, Bolt, v0, and any MCP-compatible client |
| **Fully Managed Auth** | OAuth 2.1 for every connector — no token management, no app registration, no refresh handling |
| **Governed Access** | Role-based permissions, audit trails, and enterprise compliance controls |
| **SOC 2 Certified** | Enterprise-grade security and compliance built into the platform |
| **Sub-Second Execution** | Direct API calls through the Fastn platform with built-in caching and connection pooling |
| **Multiple Transports** | stdio (local), SSE, and Streamable HTTP for any deployment model |
| **Production Ready** | Docker support, health checks, structured logging, and OAuth 2.1 protected resource metadata |
| **Flow Automation** | Create, manage, and execute multi-step workflows that compose tools |
## Quick Start
### 1. Sign up at [app.ucl.dev](https://app.ucl.dev)
Create an account and connect your first connectors (Gmail, Slack, GitHub, etc.).
### 2. Connect your MCP client
**Hosted server (recommended)** — no installation needed:
```
https://mcp.live.fastn.ai/shttp
```
Point any MCP client at this URL. Authentication is handled via MCP OAuth 2.1 automatically. See [Client Configuration](#client-configuration) for Claude Desktop and Cursor examples.
**Self-hosted** — install and run your own instance:
```bash
pip install fastn-mcp-server
fastn-mcp --shttp --port 8000
```
## Connecting to the MCP Server
### Endpoints
Use the hosted server (`mcp.live.fastn.ai`) or your self-hosted instance. Each path exposes a different set of tools:
| Endpoint | Tools |
|----------|-------|
| `/shttp` | All 11 tools: `find_tools`, `execute_tool`, `list_connectors`, `list_skills`, `list_projects`, `list_flows`, `run_flow`, `delete_flow`, `create_flow`, `update_flow`, `configure_custom_auth` |
| `/shttp/ucl` | 5 tools: `find_tools`, `execute_tool`, `list_connectors`, `list_skills`, `list_projects` |
| `/shttp/ucl/{project_id}` | 4 tools: `find_tools`, `execute_tool`, `list_connectors`, `list_skills` |
| `/shttp/ucl/{project_id}/{skill_id}` | 3 tools: `find_tools`, `execute_tool`, `list_connectors` |
| `/sse`, `/sse/ucl`, etc. | Same pattern for SSE transport |
**Examples with the hosted server:**
```
https://mcp.live.fastn.ai/shttp # All tools
https://mcp.live.fastn.ai/shttp/ucl # UCL tools only
https://mcp.live.fastn.ai/shttp/ucl/{project_id} # Pre-set project
https://mcp.live.fastn.ai/shttp/ucl/{project_id}/{skill_id} # Pre-set project + skill
```
### Authentication
The MCP server supports three authentication methods. Get your credentials from [app.ucl.dev](https://app.ucl.dev).
#### MCP OAuth 2.1 (Recommended)
Standard MCP OAuth flow with PKCE. The server bridges to Fastn's identity provider automatically. Just point your client at the URL — you'll be prompted to authenticate:
```json
{
"mcpServers": {
"fastn": {
"url": "https://mcp.live.fastn.ai/shttp"
}
}
}
```
#### Token / API Key
Pass a Fastn auth token or API key via the `Authorization` header in your MCP client config:
```json
{
"mcpServers": {
"fastn": {
"url": "https://mcp.live.fastn.ai/shttp",
"headers": {
"Authorization": "Bearer <your-token-or-api-key>"
}
}
}
}
```
You can also pass `x-project-id` to scope requests to a specific project:
```json
{
"mcpServers": {
"fastn": {
"url": "https://mcp.live.fastn.ai/shttp",
"headers": {
"Authorization": "Bearer <your-token-or-api-key>",
"x-project-id": "<your-project-id>"
}
}
}
}
```
For local stdio transport, pass credentials as environment variables:
```json
{
"mcpServers": {
"fastn": {
"command": "fastn-mcp",
"args": ["--stdio"],
"env": {
"FASTN_API_KEY": "your-api-key",
"FASTN_PROJECT_ID": "your-project-id"
}
}
}
}
```
## MCP Tools
The server exposes these tools to AI agents:
### UCL Tools
| Tool | Description |
|------|-------------|
| `find_tools` | Search for available connector tools by natural language prompt. Returns matching tools with IDs and input schemas. |
| `execute_tool` | Execute a connector tool by its ID with parameters. Returns the result directly. |
| `list_connectors` | Browse all 250+ available connectors in the registry, including ones not yet connected. |
| `list_skills` | List available skills in the project. |
| `list_projects` | List available projects for the authenticated user. |
**Workflow:** Browse connectors → `list_connectors`. Execute an action → `find_tools` → `execute_tool`. If `find_tools` returns nothing relevant → `list_connectors` (connector may need connecting).
### Flow Management
| Tool | Description |
|------|-------------|
| `list_flows` | List saved automations (flows) in the project. |
| `run_flow` | Execute a saved flow by its ID. |
| `delete_flow` | Remove a flow from the project. |
| `create_flow` | *(Under development)* Create a flow from natural language. |
| `update_flow` | *(Under development)* Update an existing flow. |
### Configuration
| Tool | Description |
|------|-------------|
| `configure_custom_auth` | Register a custom JWT auth provider (Auth0, Firebase, Supabase). |
## Architecture
```
AI Agent (Claude, Cursor, Lovable)
│
▼
MCP Protocol (stdio / SSE / Streamable HTTP)
│
▼
┌─────────────────────────────┐
│ Fastn MCP Server │
│ ┌───────────────────────┐ │
│ │ Tool Discovery │ │ find_tools, list_connectors
│ │ Tool Execution │ │ execute_tool
│ │ Flow Management │ │ list/run/delete/create flows
│ │ Auth & Config │ │ OAuth 2.1, custom JWT
│ └───────────────────────┘ │
└─────────────────────────────┘
│
▼
Fastn SDK → Fastn API
│
▼
250+ Connectors (Slack, Jira, GitHub, Salesforce, Postgres, ...)
```
**Connectors** provide tools. **Flows** compose tools. **Agents** run flows and tools with reasoning.
## Client Configuration
The JSON examples above work with any MCP client. Here are the config file locations:
| Client | Config File |
|--------|------------|
| **Claude Desktop** | `claude_desktop_config.json` |
| **Cursor** | `.cursor/mcp.json` in your project |
| **Claude Code** | `.mcp.json` in your project |
For Cursor, use the `/shttp/ucl` endpoint to expose only UCL tools (recommended for coding assistants):
```json
{
"mcpServers": {
"fastn": {
"url": "https://mcp.live.fastn.ai/shttp/ucl"
}
}
}
```
## Self-Hosting
### Transport Modes
**stdio (local)** — For pipe-based clients:
```bash
fastn-mcp --stdio
fastn-mcp --stdio --mode ucl # UCL tools only
fastn-mcp --stdio --mode ucl --project ID # UCL tools + pre-set project
fastn-mcp --stdio --mode ucl --project ID --skill ID # UCL tools + pre-set project and skill
```
**SSE + Streamable HTTP (remote)** — For web-based AI platforms:
```bash
fastn-mcp --sse --shttp --port 8000
```
### OAuth Setup
Remote transports use MCP OAuth 2.1 by default. The server implements RFC 9728 Protected Resource Metadata:
```bash
fastn-mcp --sse --shttp --port 8000
# OAuth endpoints auto-configured at /.well-known/oauth-protected-resource
```
Set the public URL for OAuth metadata:
```bash
fastn-mcp --sse --shttp --port 8000 --server-url https://mcp.example.com
```
To disable OAuth for local development:
```bash
fastn-mcp --sse --port 8000 --no-auth
```
### Docker
```bash
docker build -t fastn-mcp .
docker run -p 8000:8000 fastn-mcp
```
```bash
docker compose up -d
```
### Environment Variables
Server configuration for self-hosted deployments:
```bash
FASTN_MCP_PORT=8000
FASTN_MCP_HOST=0.0.0.0
FASTN_MCP_SERVER_URL=https://your-public-url
FASTN_MCP_TRANSPORT=both
FASTN_MCP_NO_AUTH=false
FASTN_MCP_VERBOSE=false
```
| Variable | Required | Description |
|----------|----------|-------------|
| `FASTN_MCP_PORT` | No | Server port (default: `8000`) |
| `FASTN_MCP_HOST` | No | Bind address (default: `0.0.0.0`) |
| `FASTN_MCP_SERVER_URL` | No | Public URL for OAuth metadata |
| `FASTN_MCP_NO_AUTH` | No | Set to `true` to disable OAuth (dev only) |
| `FASTN_MCP_TRANSPORT` | No | Transport mode: `sse`, `shttp`, `both` (default: `both`) |
| `FASTN_MCP_VERBOSE` | No | Set to `true` for debug logging |
### Local Development with ngrok
For local development and testing only — use ngrok to expose your local server:
```bash
# Terminal 1: Start the MCP server
fastn-mcp --shttp --port 8000 --verbose
# Terminal 2: Start ngrok tunnel
ngrok http 8000
```
Then restart with the ngrok URL so OAuth metadata resolves:
```bash
fastn-mcp --shttp --port 8000 \
--server-url https://abc123.ngrok-free.dev \
--verbose
```
For production, deploy with Docker behind a reverse proxy with a real domain.
## Development
### Setup
```bash
git clone https://github.com/fastnai/fastn-mcp.git
cd fastn-mcp
python -m venv .venv
source .venv/bin/activate
pip install -e ".[dev]"
```
### Run Tests
```bash
pytest tests/ -q
```
### Project Structure
```
fastn-mcp/
├── fastn_mcp/
│ ├── __init__.py # Package metadata
│ ├── __main__.py # CLI entry point
│ ├── server.py # MCP server, tools, handlers, routing
│ ├── auth.py # OAuth 2.1 provider (RFC 9728)
│ └── tools/ # Tool utilities
├── tests/
│ ├── test_server.py # 185+ tests covering all tools and transports
│ └── conftest.py # Test fixtures
├── Dockerfile # Production container
├── docker-compose.yml # Docker Compose for deployment
├── pyproject.toml # Python project configuration
└── README.md
```
## CLI Reference
```
fastn-mcp [OPTIONS]
Transport:
--stdio Use stdio transport (Claude Desktop, Cursor)
--sse Enable SSE transport
--shttp Enable Streamable HTTP transport
Server:
--host HOST Bind address (default: 0.0.0.0)
--port PORT Port number (default: 8000)
--no-auth Disable OAuth (development only)
--server-url URL Public URL for OAuth metadata
Mode:
--mode {agent,ucl} Tool mode for stdio: "agent" (all tools) or "ucl" (UCL tools only)
--project ID Pre-set project ID for stdio
--skill ID Pre-set skill ID for stdio (requires --project)
Debug:
-v, --verbose Enable debug logging
```
## Supported Connectors
Fastn provides 250+ pre-built connectors including:
**Communication:** Slack, Microsoft Teams, Discord, Gmail, Outlook, SendGrid, Twilio
**Project Management:** Jira, Linear, Asana, Trello, Monday.com, ClickUp, Notion
**Development:** GitHub, GitLab, Bitbucket, PagerDuty, Sentry, Datadog
**CRM & Sales:** Salesforce, HubSpot, Pipedrive, Zoho CRM
**Databases:** PostgreSQL, MySQL, MongoDB, Redis, Supabase, Firebase
**Cloud:** AWS, Google Cloud, Azure, Cloudflare
**Finance:** Stripe, QuickBooks, Xero
**And 200+ more** — browse the full catalog at [fastn.ai/integrations](https://fastn.ai/integrations)
## License
MIT
## Links
- [Fastn Platform](https://fastn.ai)
- [Fastn SDK](https://github.com/fastnai/fastn-sdk)
- [MCP Specification](https://modelcontextprotocol.io/)
- [Documentation](https://docs.fastn.ai)
