MCP Kettel

Turn routes from APIs into an MCP server.

What's in it for you

• Find API routes without running or importing the source project.
• Review discovered routes before exposing anything.
• Search, select, or clear routes from an interactive terminal checklist.
• Generate a standalone Go MCP server with only the routes you chose.
• Keep credentials out of generated source.

Features

• Static route discovery across supported backend frameworks.
• Recursive router, mount, and prefix resolution.
• Visibility for routes whose parameter schemas are not ready for generation.
• Support for GET, POST, PUT, PATCH, DELETE, OPTIONS, and HEAD.
• Primitive string, integer, float, and boolean path and query parameters.
• Deterministic MCP server generation.
• Optional upstream Authorization header forwarding.
• Safe cancellation and refusal to overwrite an existing output directory.

Quick Start

Install Go 1.24 or newer, then run Kettel against a supported API project:

go run ./cmd/mcp-kettel \
  --input /path/to/api-project \
  --output ./generated-mcp

Try the included example:

go run ./cmd/mcp-kettel \
  --input ./example/sample-project \
  --output ./generated-mcp

The checklist starts with every ready route selected. Routes marked with × were discovered but need parameter-schema support before generation. Use g to cycle grouping by source file, HTTP method, or route prefix. Groups start collapsed; highlight a group and press space to expand or collapse it. Once expanded, use space on a ready route to toggle one, a to select all ready routes, n to clear all, / to filter, enter to generate, or esc to cancel.

| Group large route sets | Filter matching APIs | | --- | --- | | | |

Run the generated server beside the running source application:

cd generated-mcp
MCP_API_BASE_URL=http://127.0.0.1:8000 go run .

For an authenticated API, set the complete header value:

MCP_API_AUTHORIZATION="Bearer $TOKEN" \
MCP_API_BASE_URL=http://127.0.0.1:8000 \
go run .

If --output is omitted, Kettel writes to <input>/mcp-server.

Kettel initially supports FastAPI and Express. Contributions that add more backend frameworks are welcome. See Contributing.

Documentation

• Architecture and data flow
• Contributing

License

Apache License 2.0. See LICENSE.