wiktionary-de-mcp

An MCP server that lets Claude (or any other MCP client) look things up in the German Wiktionary, de.wiktionary.org. Instead of answering from memory, Claude checks the dictionary itself and cites the entry.

It's useful when you want a reliable answer to questions like:

• „Gibt es das Wort ‚verschlimmbessern'?"
• "What's the gender and plural of ‚Band' in the sense of a music group?"
• "Is it ‚gewinkt' or ‚gewunken'?"
• "Conjugate ‚gehen' in Konjunktiv II."
• "Does ‚laufen' take ‚haben' or ‚sein' in the perfect tense?"

No API key or account is needed.

Tools

Entries are written in German, as on Wiktionary. The German Wiktionary also documents words from other languages, explained in German. Use lookup_word with language: "en" (or "Englisch", "French", "*" for all) to get those.

Setup

You need uv installed. uv downloads and runs the server for you (via uvx), so there is nothing else to install.

Claude Desktop

Open Settings → Developer → Edit Config, or edit claude_desktop_config.json directly:

• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
• Windows: %APPDATA%\Claude\claude_desktop_config.json

Add the server:

{
  "mcpServers": {
    "wiktionary-de": {
      "command": "uvx",
      "args": ["wiktionary-de-mcp"]
    }
  }
}

Restart Claude Desktop, then ask it something about a German word.

If Claude Desktop reports that it can't start the server, it usually can't find uvx. Desktop apps often don't see the PATH from your shell. Run which uvx (macOS) or where uvx (Windows) and put the full path in "command", for example "/Users/you/.local/bin/uvx".

Claude Code

claude mcp add --scope user wiktionary-de -- uvx wiktionary-de-mcp

--scope user makes it available in every project. Leave it out to add it to the current project only.

Other MCP clients

Any client that supports stdio servers works. Configure the command uvx with the argument wiktionary-de-mcp. If you prefer pip, install with pip install wiktionary-de-mcp and use the command wiktionary-de-mcp.

Updating

uvx caches the package. To get a newer release, run uvx wiktionary-de-mcp@latest once, or pin a version in the config with "args": ["wiktionary-de-mcp@0.2.0"].

Good to know

• Grammar is per word. Wiktionary records the grammar of individual words: gender, plural, cases, conjugation, auxiliary verb. It doesn't explain general rules such as when to use the dative or where commas go. Claude answers those from its own knowledge.
• Wiktionary isn't exhaustive. Not finding a word doesn't prove it isn't German. Many valid compounds (Donaudampfschifffahrt) have no entry of their own.
• Privacy. The server sends only the words you look up to the public Wikimedia API at de.wiktionary.org. Nothing else leaves your machine. Responses are cached in memory for 15 minutes.

Development

git clone https://github.com/joelbarmettlerUZH/wiktionary-mcp
cd wiktionary-mcp
uv sync
uv run pytest -m "not network"   # offline tests
uv run pytest                    # also runs live tests against de.wiktionary.org
npx @modelcontextprotocol/inspector uv run wiktionary-de-mcp   # try the tools interactively

To use your local checkout from Claude Desktop, use this server entry:

"wiktionary-de": {
  "command": "uv",
  "args": ["run", "--directory", "/path/to/wiktionary-mcp", "wiktionary-de-mcp"]
}

The code is small: server.py defines the tools, wikitext.py turns Wiktionary's page source into readable text, and client.py talks to the MediaWiki API.

Releasing

Every push to main runs release.yml. If the version in pyproject.toml isn't on PyPI yet, the workflow tests, builds and publishes the package with Trusted Publishing (no stored token). It then creates a matching vX.Y.Z GitHub release. If that version is already on PyPI, it does nothing. To release:

uv version --bump patch   # or minor / major; updates pyproject.toml and uv.lock
git commit -am "Release vX.Y.Z" && git push

License

The code is licensed under the Apache License 2.0. Dictionary content returned by the tools comes from Wiktionary contributors and is licensed under CC BY-SA 4.0.