Xcomet MCP Server

MCP Server for xCOMET translation quality evaluation

Local serverstdioPython

What is the Xcomet MCP server?

Most developer tooling work still happens through a UI a human drives. Xcomet MCP server moves it into the conversation instead. MCP Server for xCOMET translation quality evaluation.

The short version

Translation quality evaluation MCP Server powered by xCOMET (eXplainable COMET).

The tools it exposes

The server publishes 3 tools. What each one is for:

  • xcomet_evaluate — Evaluate translation quality for a single source-translation pair
  • xcomet_detect_errors — The xcomet_detect_errors tool exposed by this server
  • xcomet_batch_evaluate — The xcomet_batch_evaluate tool exposed by this server

What it needs from you

Configuration is passed through the environment: XCOMET_PYTHON_PATH, DEEPL_API_KEY, XCOMET_MODEL, XCOMET_PRELOAD. Treat anything key-shaped as a real credential — scope it to the minimum the server needs, and rotate it if it ever lands in a shared config.

Getting it running

The server ships on npm as xcomet-mcp-server, so your MCP client can launch it on demand — there is no separate build step. Add the server block to your client's configuration, restart it, and the tools register themselves.

How it compares

This sits in the developer tooling group, where several servers overlap in what they claim to do but differ sharply once you actually set them up. Xcomet's toolset — xcomet_evaluate, xcomet_detect_errors, xcomet_batch_evaluate — is a fair guide to whether it matches your workflow. It is maintained by shuji-bonji; worth a glance at recent repository activity before you build anything load-bearing on it.

We check each listing at SyncDev against the project's documentation before it goes live — if something here drifts out of date, it is a bug worth reporting.

Things to watch

  • It runs with your machine's permissions. That is convenient and also the reason to think about what you point it at before you approve a tool call.
  • Missing credentials fail quietly in some clients — if no tools show up, check the environment block first.
  • Keep per-call confirmation enabled while you learn its behaviour; it is the cheapest safeguard you have.

Available tools

ToolWhat it does
xcomet_evaluateEvaluate translation quality for a single source-translation pair.
xcomet_detect_errorsThe xcomet_detect_errors tool exposed by this server.
xcomet_batch_evaluateThe xcomet_batch_evaluate tool exposed by this server.

How to install the Xcomet MCP server

Then configure:
```json
{
  "mcpServers": {
    "xcomet": {
      "command": "xcomet-mcp-server",
      "env": {
        "XCOMET_PYTHON_PATH": "~/.xcomet-venv/bin/python3"
      }
    }
  }
}

Configuration as documented by the project. Restart the client after saving.

Configuration

VariableDescriptionRequired
XCOMET_PYTHON_PATHFilesystem location the server is allowed to use.Optional
DEEPL_API_KEYCredential the server authenticates with.Yes
XCOMET_MODELConfiguration value read at startup.Optional
XCOMET_PRELOADConfiguration value read at startup.Optional

Example prompts to try

  • Use Xcomet to xcomet evaluate.
  • Use Xcomet to xcomet detect errors.
  • Use Xcomet to xcomet batch evaluate.

Frequently asked questions

It connects Xcomet to MCP-compatible AI assistants such as Claude and Cursor, exposing 3 tools (xcomet_evaluate, xcomet_detect_errors, xcomet_batch_evaluate) that the assistant can call on your behalf. Instead of copying data back and forth by hand, the assistant works with Xcomet directly.