@mukundakatta/json5-mcp

MCP server for JSON5: parse JSON-with-comments, trailing commas, unquoted keys, hex / NaN / Infinity. Round-trip to strict JSON when downstream tools require it.

Tools

• parse_json5(text) — loose parse to a real value
• to_json5(value, indent?) — serialize for human-edited config
• to_strict_json(text, indent?) — JSON5 in, strict JSON out

Why this exists

LLMs frequently emit JSON-with-comments thinking it's JSON. They also see config files (tsconfig, .babelrc, mcp.json) that are JSON5 in disguise. This server is the loose-parse + strict-emit round trip — feed it whatever the LLM produced, get back something JSON.parse accepts.

Install — Claude Desktop

{
  "mcpServers": {
    "json5": { "command": "npx", "args": ["-y", "@mukundakatta/json5-mcp"] }
  }
}

Same shape for Cursor / Cline / Windsurf / Zed.

License

MIT OR Apache-2.0.