MCP-Gateway

# MCP Gateway

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The production platform for MCP tools.

Claude Desktop can connect to your internal tools — databases, filesystems, APIs, anything — through a single authenticated endpoint. You control who can use which tools, every action is logged, and no raw credentials ever leave your server.

Built-in tools: SQL query (Postgres, MySQL, SQLite, MSSQL), filesystem access.
Custom tools: plug in anything that implements the MCP tool interface.

> **[See it in action](docs/media/local_demo.mp4)** — short demo of Claude Desktop querying a database through MCP Gateway.

## Table of Contents

- [Overview](#overview)
- [Features](#features)
- [Architecture](#architecture)
- [Quick Start](#quick-start)
- [Configuration](#configuration)
- [Authentication](#authentication)
- [API Reference](#api-reference)
- [MCP Integration](#mcp-integration)
- [Role-Based Access Control](#role-based-access-control)
- [Entra ID / SSO](#entra-id--sso)
- [Development](#development)
- [Troubleshooting](#troubleshooting)
- [Security](#security)
- [Additional Documentation](#additional-documentation)

---

## Overview

MCP Gateway sits between AI assistants and your databases. It:

1. Authenticates users via password login, Microsoft Entra ID (Azure AD), or API keys
2. Enforces role-based access control (viewer / analyst / admin)
3. Exposes databases as MCP tools that AI assistants can discover and call
4. Translates natural language questions into SQL via Claude, executes queries, and summarizes results
5. Logs all activity to a structured audit trail

```
Claude Desktop / mcp-remote
        │
        │ MCP over SSE (OAuth 2.1 + PKCE)
        ▼
┌─────────────────────────────────────────────────────────┐
│                      MCP Gateway                        │
│                                                         │
│  ┌──────────┐  ┌──────────┐  ┌───────────────────────┐ │
│  │ Auth /   │  │  Admin   │  │   MCP SSE Endpoint    │ │
│  │ OAuth    │  │   UI     │  │  /t/{slug}/mcp/sse    │ │
│  └──────────┘  └──────────┘  └───────────────────────┘ │
│                                          │              │
│  ┌──────────────────────────────────────┐│              │
│  │         Tool Providers               ││              │
│  │  sql.py → get_schema / execute_sql   ││              │
│  └──────────────────────────────────────┘│              │
└─────────────────────────────────────────┼───────────────┘
                                          │ Decrypted DSN
                    ┌─────────────────────┼────────────────┐
                    │   Your Databases    │                │
                    │  Postgres  MySQL  MSSQL  SQLite      │
                    └────────────────────────────────────  ┘
```

---

## What you get out of the box

**For your organisation**
- One URL for Claude Desktop — users authenticate once, access everything they're allowed
- Microsoft Entra ID SSO — roles assigned automatically from Azure AD groups
- Full audit trail — every tool call, every query, every login, who did what and when

**For your tools**
- Drop any MCP tool into the gateway and it inherits auth, RBAC, and logging automatically
- Per-tool role overrides — restrict SQL execution to analysts, filesystem writes to admins
- Bundled: SQL tools (4 databases), filesystem tools (read, write, search, tree)

**For your security team**
- No credentials on employee machines
- Tenant isolation — org A cannot see org B's tools or data
- API keys for CI/CD, OAuth 2.1 + PKCE for human users

### Supported Databases
| Database | Driver | DSN Format |
|----------|--------|------------|
| PostgreSQL | psycopg2 | `postgresql://user:pass@host/db` |
| MySQL / MariaDB | PyMySQL | `mysql+pymysql://user:pass@host/db` |
| Microsoft SQL Server | pymssql | `mssql+pymssql://user:pass@host/db` |
| SQLite | Built-in | `sqlite:///path/to/file.db` |

### Filesystem Tools
- Sandboxed file read/write/search exposed as MCP tools
- Enabled via `FILESYSTEM_ALLOWED_DIRS` environment variable
- Read operations (analyst+): `fs_read_file`, `fs_list_directory`, `fs_directory_tree`, `fs_search_files`, `fs_get_file_info`
- Write operations (admin): `fs_write_file`, `fs_create_directory`, `fs_move_file`

### Admin UI
- Web interface served at `/admin/`
- Manage connections, users, SSO config, API keys, and tool roles
- View audit logs, generated SQL, and query results

---

## Architecture

### Technology Stack

| Layer | Technology | Version |
|-------|-----------|---------|
| API Framework | FastAPI | 0.131.0 |
| ASGI Server | Uvicorn | 0.34.0 |
| ORM | SQLAlchemy | 2.0.30 |
| Migrations | Alembic | 1.13.1 |
| Auth / JWT | PyJWT + bcrypt | 2.12.0 / 4.0.1 |
| Encryption | cryptography (Fernet) | 46.0.5 |
| LLM | Anthropic SDK | 0.42.0 |
| MCP Protocol | mcp | 1.23.0 |
| SQL Validation | sqlglot | 25.1.0 |
| Rate Limiting | slowapi | 0.1.9 |
| Frontend | React 18 + TypeScript + Vite | — |

### Project Structure

```
app/
├── main.py               # FastAPI app setup, middleware, routing
├── config.py             # Environment config (Pydantic Settings)
├── database.py           # SQLAlchemy engine + session factory
├── api/
│   ├── auth.py           # POST /auth/login
│   ├── auth_entra.py     # Entra SSO (legacy admin UI paths)
│   ├── oauth.py          # OAuth 2.1 endpoints (/t/{slug}/oauth/*)
│   ├── connections.py    # DB connection CRUD
│   ├── query.py          # Natural language query endpoint
│   ├── tenants.py        # Tenant + user management
│   ├── tools.py          # Tool listing + role overrides
│   ├── mcp_sse.py        # MCP SSE transport
│   ├── api_keys.py       # API key management
│   └── audit_logs.py     # GET /audit-logs/ (admin)
├── core/
│   ├── auth.py           # JWT creation/validation, password hashing
│   ├── dependencies.py   # FastAPI dependency injection
│   ├── rbac.py           # Role hierarchy helpers
│   ├── security.py       # Fernet encrypt/decrypt
│   ├── api_keys.py       # API key generation + hashing
│   ├── limiter.py        # slowapi rate limiter setup
│   └── log_filter.py     # Health-check log noise filter
├── constants.py          # Non-tunable application-wide constants (pagination caps, etc.)
├── models/__init__.py    # All SQLAlchemy ORM models
├── schemas/__init__.py   # All Pydantic request/response schemas
├── services/
│   ├── entra.py          # Microsoft Graph API client
│   ├── llm.py            # Anthropic API (SQL gen + summarization)
│   ├── mcp_client.py     # Direct SQLAlchemy schema introspection + query execution
│   └── audit.py          # Audit log writer
└── tools/
    ├── __init__.py       # Tool provider framework + registry
    ├── sql.py            # DB schema + execute_sql tools
    ├── example.py        # Example custom tools
    └── filesystem.py     # Sandboxed file read/write/search tools

frontend/src/
├── App.tsx               # Root component, auth context, tab routing
├── api.ts                # API client, token management
├── types.ts              # TypeScript types (mirrors Pydantic schemas)
├── constants.ts          # Frontend constants (timeouts, retry config)
└── components/
    ├── Login.tsx          # Sign-in form
    ├── Setup.tsx          # Tenant registration
    ├── Dashboard.tsx      # Tenant info + role display
    ├── Connections.tsx    # DB connection management
    ├── Query.tsx          # Natural language query UI
    ├── Users.tsx          # User management (admin)
    ├── SsoConfig.tsx      # Entra ID configuration (admin)
    ├── Tools.tsx          # Tool browser + role overrides
    ├── ApiKeys.tsx        # API key management
    └── AuditLog.tsx       # Filterable audit log viewer (admin)
```

### Database Schema

```
Tenants ─┬─► Users ──────► APIKeys
         ├─► DBConnections
         ├─► TenantEntraConfig
         ├─► AuditLogs
         ├─► OAuthStates
         ├─► OAuthAuthorizationCodes
         ├─► OAuthRefreshTokens
         └─► ToolRoleOverrides
```

---

## Quick Start

### Prerequisites

- Docker and Docker Compose
- An Anthropic API key (for the `/query/` endpoint; not needed for raw MCP tool access)

### 1. Clone and configure

```bash
git clone <repo-url>
cd MCP-Gateway
cp .env.example .env
```

Edit `.env`:

```bash
# Required — generate unique values
SECRET_KEY=<random 64-char string>
ENCRYPTION_KEY=<random string, min 32 chars — longer is better>
POSTGRES_PASSWORD=<strong password>

# Required for natural language query
ANTHROPIC_API_KEY=sk-ant-...

# Update to your server's public URL in production
BASE_URL=http://localhost:8000
```

Generate secure random values:

```bash
# SECRET_KEY
python3 -c "import secrets; print(secrets.token_hex(32))"

# ENCRYPTION_KEY (min 32 chars; full key consumed via BLAKE2b derivation)
python3 -c "import secrets; print(secrets.token_hex(32))"
```

### 2. Start the stack

```bash
docker compose up -d
```

Services started:
- `api` on port **8000** (FastAPI + admin UI)
- `db` on port 5432 (PostgreSQL, internal only)

### 3. Register your first tenant

```bash
curl -s -X POST http://localhost:8000/tenants/ \
  -H "Content-Type: application/json" \
  -d '{
    "name": "My Organization",
    "slug": "my-org",
    "admin_email": "admin@example.com",
    "admin_password": "SuperSecret123!"
  }' | jq
```

The `slug` becomes part of your MCP URL: `http://localhost:8000/t/my-org/mcp/sse`

### 4. Open the admin UI

Navigate to **http://localhost:8000/admin/** and sign in with your admin credentials.

### 5. Add a database connection

In the admin UI → **Connections** → **Create connection**, or via API:

```bash
TOKEN=$(curl -s -X POST http://localhost:8000/auth/login \
  -H "Content-Type: application/json" \
  -d '{"email":"admin@example.com","password":"SuperSecret123!"}' \
  | jq -r .access_token)

curl -s -X POST http://loc