uni-mcp-gateway

A unified MCP (Model Context Protocol) gateway that aggregates multiple MCP servers and API plugins behind a single endpoint — with authentication, granular rate limiting, audit logging, a REST API bridge, and a web dashboard.

Connect your AI agents to dozens of services through one URL, one API key, one audit trail.

Why We Built This

We run AI agents across dozens of environments — Cursor, Claude Desktop, Opencode, custom bots. Every environment needs its own MCP connections, its own auth, its own config. It breaks constantly and scales terribly. Here's what drove us to build this:

Re-auth hell. Every time you add a new IDE, a new agent, or a new machine, you re-authenticate every MCP server from scratch. With a gateway, you authenticate once. Every environment just needs one URL and one API key.

Context window bloat. Connect 5 MCP servers with 50 tools each and your agent's context window is stuffed with 250 tool schemas before it even starts working. The gateway's meta-tool architecture (list_plugins → search_tools → get_tool_schema → call_tool) means only 4 tools in context, always. Agents discover what they need on demand.

Multi-account chaos. Need two Slack workspaces? Three Calendly accounts? Five email inboxes? Without a gateway, that's 10 separate MCP servers with 10x the tools. The gateway handles multi-account natively — one plugin, one set of tools, pass account="work" or account="personal".

Agents don't need API docs. The gateway doubles as a REST API bridge. Any tool is callable via POST /api/v1/call. No Swagger specs, no SDK setup — agents (and scripts) just call tools by name with JSON params. The gateway is the API.

Audit and access control, finally. Share API keys with people or agents and know exactly what they did. Every tool call is logged with full request, response, duration, and caller. Set granular scopes — this key can read Slack but not send, can access the "work" Calendly but not "personal", can call gmail_messages_list 30 times per minute but gmail_messages_send only 5.

Features

Core

• Unified endpoint — One MCP URL, one API key, access to everything
• Plugin architecture — Drop a Python file in plugins/, restart, done
• External MCP bridging — Proxy any remote MCP server through the gateway (no code needed)
• REST API bridge — Every tool is also available via standard HTTP GET/POST endpoints
• Web dashboard — Login, view stats, manage keys, browse audit logs

Security

• API key authentication — Multiple keys with independent permissions
• Per-plugin access control — Read, write, or admin access per plugin per key
• Granular rate limiting — Global per-key, per-plugin, per-account, per-tool limits
• IP allowlisting — Restrict keys to specific CIDR ranges
• Key expiry — Auto-expiring API keys
• Stealth mode — Unauthorized API requests return 404 (endpoint appears to not exist)
• Audit logging — Every tool call logged with request, response, duration, and caller

Multi-tenancy

• Multi-account plugins — Multiple accounts per service (e.g., two Slack workspaces, three Calendly accounts)
• Data-level scoping — Restrict keys to specific data subsets (e.g., WhatsApp chat JIDs)
• Tool visibility filtering — Keys only see tools they have access to

Context Window Optimization

• Meta-tool architecture — Instead of exposing 300+ tools to the agent, exposes 4 meta-tools:
  • list_plugins — See what's available
  • search_tools — Find tools by keyword
  • get_tool_schema — Get parameters for a specific tool
  • call_tool — Execute any tool

Quick Start

1. Clone and install

git clone https://github.com/nickcold/uni-mcp-gateway.git
cd uni-mcp-gateway
pip install -e .

2. Set your admin token

export MCP_AUTH_TOKEN=$(python3 -c "import secrets; print(secrets.token_urlsafe(32))")
export MCP_BASE_URL=http://localhost:8080
export GATEWAY_DB_PATH=./gateway.db
echo "Your admin token: $MCP_AUTH_TOKEN"

3. Run

python -m uvicorn main:app --host 0.0.0.0 --port 8080

4. Connect

Add to your MCP client (Cursor, Claude Desktop, etc.):

{
  "mcpServers": {
    "gateway": {
      "url": "http://localhost:8080/mcp",
      "headers": {
        "Authorization": "Bearer YOUR_ADMIN_TOKEN"
      }
    }
  }
}

Or use the REST API:

# List plugins
curl -H "Authorization: Bearer $MCP_AUTH_TOKEN" http://localhost:8080/api/v1/plugins

# Call a tool
curl -X POST -H "Authorization: Bearer $MCP_AUTH_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"tool": "gmail_messages_list", "params": {"max_results": "5"}}' \
  http://localhost:8080/api/v1/call

Adding Plugins

Option A: Write a plugin (wrap any API)

Copy plugins/_example.py and modify:

from plugin_base import MCPPlugin, ToolDef, get_credentials

def list_items(query: str = "") -> dict:
    """List items from the API."""
    api_key = get_credentials("myservice").get("api_key", "")
    # ... call the API ...
    return {"items": [...]}

class MyServicePlugin(MCPPlugin):
    name = "myservice"
    tools = {
        "list_items": ToolDef(access="read", handler=list_items, description="List items"),
    }

Restart the gateway. Your tools appear as myservice_list_items.

Option B: Bridge an external MCP (no code)

Connect to any remote MCP server through the admin tools or dashboard:

gateway_add_external_mcp(
    name="acme",
    url="https://acme-mcp.example.com/mcp",
    auth_header="Bearer their-api-key"
)

The gateway discovers all tools from the remote server and exposes them as acme_<tool_name> — wrapped with your auth, rate limiting, and audit logging.

Option C: Dashboard UI

Go to http://localhost:8080/dash, log in with your admin key, switch to the External MCPs tab, and fill in the form.

Managing API Keys

Create keys for your team or agents with different permission levels:

# Via MCP tools
gateway_create_key(
    key_id="staging-bot",
    label="Staging Bot",
    permissions={"gmail": "read", "slack": "write"},
    rate_limit=50
)

# Via REST API
POST /api/v1/call
{"tool": "gateway_create_key", "params": {"key_id": "staging-bot", ...}}

# Via dashboard
http://localhost:8080/dash/admin → Keys tab → + Create Key

Granular Rate Limits

Set limits at any level of granularity:

# Per plugin: max 30 Gmail calls/min
gateway_set_rate_limit(key_id="staging-bot", scope="plugin:gmail", rate_limit=30)

# Per account: max 10 calls/min to the "work" Calendly account
gateway_set_rate_limit(key_id="staging-bot", scope="account:calendly:work", rate_limit=10)

# Per tool: max 5 email sends/min
gateway_set_rate_limit(key_id="staging-bot", scope="tool:gmail_messages_send", rate_limit=5)

Bundled Plugins

Plugin	Service	Description
gmail	Google Gmail API	Full email management (send, read, labels, drafts, filters, delegates)
calendly	Calendly API	Event types, scheduled events, invitees, routing forms
linear	Linear API	Issues, projects, teams, comments, labels
notion	Notion API	Pages, databases, blocks, search
slack	Slack Web API	Messages, channels, users, reactions, files, user groups
bison	EmailBison API	Email campaign management, warmup, workspaces
ai_ark	AI Ark API	People/company search, email finder, phone lookup
whatsapp	WhatsApp (self-hosted bridge)	Send/receive messages, media, contacts (requires Go bridge)

All plugins wrap public APIs. Remove any you don't need by deleting the file from plugins/.

Deploying to Fly.io

cp fly.toml.example fly.toml
# Edit fly.toml — set app name, region, MCP_BASE_URL

fly launch --no-deploy
fly secrets set MCP_AUTH_TOKEN=$(python3 -c "import secrets; print(secrets.token_urlsafe(32))")
fly volumes create gateway_data --size 1 --region iad
fly deploy

Architecture

┌─────────────────────────────────────────────┐
│              MCP Client (Agent)             │
│         (Cursor, Claude, Opencode)          │
└─────────────┬───────────────────────────────┘
              │ MCP Protocol (Streamable HTTP)
              │ or REST API (/api/v1/*)
              ▼
┌─────────────────────────────────────────────┐
│           uni-mcp-gateway                   │
│                                             │
│  ┌─────────┐ ┌──────────┐ ┌─────────────┐  │
│  │  Auth   │ │  Audit   │ │ Rate Limit  │  │
│  └────┬────┘ └────┬─────┘ └──────┬──────┘  │
│       │           │              │          │
│  ┌────▼───────────▼──────────────▼──────┐   │
│  │          Plugin Registry             │   │
│  │  ┌──────┐ ┌──────┐ ┌──────────────┐  │   │
│  │  │Gmail │ │Slack │ │External MCPs │  │   │
│  │  └──────┘ └──────┘ └──────────────┘  │   │
│  └──────────────────────────────────────┘   │
│                                             │
│  ┌────────────┐ ┌───────────────────────┐   │
│  │  Dashboard │ │  REST API Bridge      │   │
│  └────────────┘ └───────────────────────┘   │
└─────────────────────────────────────────────┘

Configuration

Env Variable	Default	Description
MCP_AUTH_TOKEN	(required)	Admin API key for bootstrapping
MCP_BASE_URL	http://localhost:8080	Public URL of the gateway
GATEWAY_DB_PATH	/data/gateway.db	SQLite database path
ADMIN_KEY_ID	admin	ID for the admin key
PORT / MCP_PORT	8080	Server port
WHATSAPP_BRIDGE_URL	http://localhost:7481	WhatsApp Go bridge URL

License

MIT