fix(mcp): connect the stdio transport when serve.js requires the server - #11
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theanshsonkar merged 1 commit intoAug 4, 2026
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src/cli/serve.js loads the MCP server with a bare require(), but
src/mcp/server.js only calls server.connect() under
`if (require.main === module)`. Required through the `carto` bin,
require.main is src/cli/index.js, so the guard is false, main() never runs,
and the process sits with an unconnected server — it prints
'MCP server starting...' and then never answers a request.
Every config `carto init` writes uses `{ command: 'carto', args: ['serve'] }`,
so this affects all MCP hosts rather than any one of them.
Exports main() and calls it from serve.js, keeping the require.main guard so
`node src/mcp/server.js` still works.
Verified against a real container: a tools/list handshake through
`carto serve` returns 0 bytes before this change and the full 10-tool core
tier after it.
Fixes theanshsonkar#9
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NOTE: PR DESCRIPTION WAS MADE USING CLAUDE CODE.
I have reviewed it personally, but just wanted to let you know.
Fixes #9.
src/cli/serve.jsloads the MCP server with a barerequire(), butsrc/mcp/server.jsonly callsserver.connect()underif (require.main === module). Required through thecartobin,require.mainissrc/cli/index.js, so the guard is false,main()never runs, and the process sits with an unconnected server — it prints[CARTO] MCP server starting...and then never answers a request.Every config
carto initwrites uses{ command: 'carto', args: ['serve'] }, so this affects all MCP hosts rather than any one of them.Change
Export
main()and call it fromserve.js. Therequire.main === moduleguard stays, sonode src/mcp/server.jskeeps working as before. Errors from the explicit call are logged and exit non-zero, matching what the guard already did.Verification
A
tools/listhandshake throughcarto serveagainst a real container:npm testpasses (420 tests).I left the fix minimal since
src/mcp/server.jsis Tier 3 in CONTRIBUTING.md. Happy to reshape it if you'd rather the CLI own the transport, or if you'd preferserve.jsnot swallow the error.