Servers in other languages

toolproof only talks MCP to the server, so the server can be written in anything. Put the command that starts it in server.command; toolproof itself still runs on Python.

TypeScript / NodePublished npm packageGo / Rust / any binaryDockerPython with uvx

server:
  command: ["node", "dist/index.js"]

Build first (npm run build). Pointing at the built file starts faster and more reliably than npx or ts-node, which matters because toolproof restarts the server after a crash.

server:
  command: ["npx", "-y", "@modelcontextprotocol/server-memory"]

On Windows, use npx.cmd, or install the package locally and run node node_modules/<package>/dist/index.js.

server:
  command: ["./bin/my-server", "--stdio"]

server:
  command: ["docker", "run", "-i", "--rm", "my-org/my-server:latest"]

-i keeps stdin open, which stdio servers need.

server:
  command: ["uvx", "mcp-server-time"]

Environment variables

A stdio server only inherits a small set of environment variables (see Configuration). Pass anything else explicitly:

server:
  command: ["node", "dist/index.js"]
  env:
    API_KEY: "${API_KEY}"
    LOG_LEVEL: error

Server logs

toolproof captures the server's stderr instead of printing it. When the server fails to start or crashes during a test, the last lines are shown in the report, so logging to stderr is the easiest way to see why.