Install

Install

Stdio MCP transports must keep stdout reserved for JSON-RPC. Use the package bin (npx -y run402-mcp) or node dist/index.js from a built checkout. If a host insists on npm start, set npm_config_loglevel=silent; npm’s lifecycle banner is stdout and otherwise appears as non-JSON prelude. The repo .npmrc and Docker image set this for source/container hosts.

The server needs Node.js 22.13 or later (the run tool strips TypeScript types with Node’s own stripTypeScriptTypes). It installs as plain JavaScript and WebAssembly: no compiler, no native addon.

Paying needs the LOCAL server. An x402 payment is signed with a key, so the wallet-less remote (mcp.run402.com/mcp) cannot make one; it can only decode a challenge (x402_price_check).

The server acts as the wallet the CLI would pick in its working directory (RUN402_WALLET, else the nearest .run402.json binding, else the global default). Set RUN402_WALLET in the host’s server config to pin one.

Claude Desktop

Add to ~/Library/Application Support/Claude/claude_desktop_config.json:

{
  "mcpServers": {
    "run402": { "command": "npx", "args": ["-y", "run402-mcp"] }
  }
}

Cursor

Add to .cursor/mcp.json:

{
  "mcpServers": {
    "run402": { "command": "npx", "args": ["-y", "run402-mcp"] }
  }
}

Cline

Add to your Cline MCP settings (same shape as above).

Claude Code

claude mcp add run402 -- npx -y run402-mcp

See also

• Wayfinder: https://run402.com/llms.txt
• SDK reference: https://docs.run402.com/llms-sdk.txt
• CLI reference: https://docs.run402.com/llms-cli.txt
• HTTP API reference: https://run402.com/llms-full.txt
• Site: https://run402.com

Native PostgREST permission denial is a separate boundary: an exposed table can still reject an operation with HTTP 401/403 and SQLSTATE 42501. SDK/CLI/MCP label that REST_PERMISSION_DENIED, retaining source: postgrest, upstream status/code, requested method/relation, and the original body. It does not establish whether grants or RLS caused the denial, and it is not TABLE_NOT_EXPOSED.