Datamuse MCP

MCP server for the Datamuse API (word search, rhymes, synonyms, and more).

This project is open source, free to use, and licensed under MIT.

About

datamuse-mcp is a local stdio MCP server that wraps Datamuse endpoints into validated MCP tools. It is designed for practical word-finding use cases in assistants and clients that support MCP.

Purpose

This server provides simple MCP tools to:

• find synonyms, antonyms, and rhymes;
• run autocomplete;
• fetch lexical details (definitions, POS, syllables, pronunciation, frequency);
• search by spelling pattern (*, ?) or phonetic similarity.

Requirements

• Node.js >= 18
• npm

Install

npm install

Development

npm run dev

Build & run

npm run build
npm start

Manual JSON-RPC checks

# List tools
echo '{"jsonrpc":"2.0","id":1,"method":"tools/list"}' | node dist/index.js

# Call a tool
echo '{"jsonrpc":"2.0","id":2,"method":"tools/call","params":{"name":"find_synonyms","arguments":{"word":"happy"}}}' | node dist/index.js

More tool examples

{ "tool": "find_antonyms", "arguments": { "word": "happy", "max": 10 } }
{ "tool": "find_rhymes", "arguments": { "word": "love", "type": "perfect", "max": 20 } }
{ "tool": "find_similar_sounding", "arguments": { "text": "definately", "max": 15 } }
{ "tool": "find_by_pattern", "arguments": { "pattern": "s??r?", "meaning_hint": "celestial", "max": 25 } }
{ "tool": "find_related_words", "arguments": { "word": "music", "relation_type": "triggers", "max": 15 } }
{ "tool": "get_word_info", "arguments": { "word": "serendipity" } }
{ "tool": "autocomplete", "arguments": { "prefix": "astro", "max": 10 } }

Claude Desktop configuration

Add this to claude_desktop_config.json:

{
  "mcpServers": {
    "datamuse": {
      "command": "node",
      "args": ["/absolute/path/to/datamuse-mcp/dist/index.js"]
    }
  }
}

Exposed tools

• find_synonyms
• find_antonyms
• find_rhymes
• find_similar_sounding
• find_by_pattern
• find_related_words
• find_adjectives_for_noun
• find_nouns_for_adjective
• get_word_info
• autocomplete

Security and limits

• The server runs over stdio (local usage recommended).
• Outbound requests go to https://api.datamuse.com.
• A local in-memory cache is used (5-minute TTL), with no disk persistence.
• Datamuse may enforce request limits/quotas.

Publishing

For npm and MCP Registry deployment, see PUBLISHING.md.

Contributing

See CONTRIBUTING.md.

License

MIT — see LICENSE.