MCP Gateway
Discover which agents use which MCP tools by routing traffic through a NodeLoom proxy — no SDK required.
How It Works
The MCP Gateway is a reverse proxy that sits between your agent and its MCP server. Instead of your agent connecting directly to the MCP server, it connects through NodeLoom's gateway. Every tool call is observed and recorded — the gateway never modifies requests or responses.
# Before: agent → MCP server directly
MCP_SERVER_URL=http://localhost:3001/mcp
# After: agent → NodeLoom gateway → MCP server
MCP_SERVER_URL=https://your-nodeloom.com/mcp/gateway/YOUR_GATEWAY_TOKENWhat It Observes
| MCP Method | What NodeLoom Records |
|---|---|
tools/call | Tool name, duration, success/failure |
tools/list | Available tools on the server |
resources/read | Resource access patterns |
initialize | New session start |
What it doesn't see
Setup
Create a gateway
Go to Agent Inventory → MCP Gateways → New Gateway. Enter a name, the upstream MCP server URL, and optionally an agent identifier to tag all traffic with an agent name.
Copy the proxy URL
Click Copy proxy URL on the gateway card. The URL looks like /mcp/gateway/<token>.
Update your agent config
Replace your agent's MCP server URL with the gateway proxy URL. Your agent now routes all MCP traffic through NodeLoom.
View tool calls
Click View tool calls on the gateway card to see a live feed of every tool call flowing through.
Auto-Discovery
When you set an Agent Identifier on the gateway, NodeLoom automatically creates a discovered agent in your inventory with MCP_GATEWAY as the source. Every unique tool name observed through the gateway is tracked as an MCP_SERVER dependency on that agent.
This means you get a complete map of which agents use which MCP tools — without touching your agent's code.
Example
If you create a gateway named slack-mcp with agent identifier slack-assistantand your agent calls slack-send-message and slack-read-channel through it, your inventory will show:
- Agent: slack-assistant (source: MCP_GATEWAY)
- MCP Server dependency: slack-send-message (server: slack-mcp)
- MCP Server dependency: slack-read-channel (server: slack-mcp)
Getting Full Observability
The MCP gateway tells you what tools your agent uses. To see why and how — LLM prompts, token costs, anomalies, guardrail violations — add the NodeLoom SDK to your agent. Click Onboard on the agent's detail page for setup instructions.