MCP Server exits after startup, no debug.

[bdmorin]

Bug report

Describe the bug

New install, macos

➜ neofetch --backend off
-----------------
OS: macOS 15.3.1 24D70 arm64
Host: Mac15,7
Kernel: 24.3.0
Uptime: 3 days, 5 hours, 36 mins
Packages: 373 (brew)
Shell: fish 4.0.1
Resolution: 3008x1692, 1728x1117, 1440x2560
DE: Aqua
WM: Rectangle
Terminal: iTerm2
Terminal Font: ComicShannsMonoNFM-Regular 16
CPU: Apple M3 Pro
GPU: Apple M3 Pro
Memory: 3325MiB / 18432MiB

(PAT have already been deleted)

➜ npx -y @supabase/mcp-server-supabase@latest --access-token sbp_93cf52ac8a0a94277fa28e670c4cf744dc418cd8
npm warn deprecated @npmcli/[email protected]: This functionality has been moved to @npmcli/fs
npm warn deprecated [email protected]: This module is not supported, and leaks memory. Do not use it. Check out lru-cache if you want a good and tested way to coalesce async requests by a key value, which is much more comprehensive and powerful.
npm warn deprecated [email protected]: This package is no longer supported.
npm warn deprecated [email protected]: This package is no longer supported.
npm warn deprecated [email protected]: Rimraf versions prior to v4 are no longer supported
npm warn deprecated [email protected]: This package is no longer supported.
npm warn deprecated [email protected]: This package is no longer supported.
npm warn deprecated [email protected]: Glob versions prior to v9 are no longer supported
npm warn deprecated [email protected]: This package is no longer supported.
npm warn deprecated [email protected]: This package is no longer supported.

It exits with no more output.

I tried with multiple invocations.

❯ history |rg "supabase" | rg npx
npx -y @supabase/mcp-server-supabase@latest --access-token sbp_93cf52ac8a0a94277fa28e670c4cf744dc418cd8
/opt/homebrew/Cellar/node@18/18.20.8/bin/npx -y @supabase/mcp-server-supabase@latest --access-token sbp_93cf52ac8a0a94277fa28e670c4cf744dc418cd8
/opt/homebrew/Cellar/node@20/20.19.0_1/bin/npx -y @supabase/mcp-server-supabase@latest --access-token sbp_93cf52ac8a0a94277fa28e670c4cf744dc418cd8
/opt/homebrew/Cellar/node@22/22.14.0_1/bin/npx -y @supabase/mcp-server-supabase@latest --access-token sbp_93cf52ac8a0a94277fa28e670c4cf744dc418cd8

All with the exact same output.

I tried with a mcp debugger:

❯ npx mcp-chat --server "npx -y @supabase/mcp-server-supabase@latest --access-token sbp_93cf52ac8a0a94277fa28e670c4cf744dc418cd8"
npm warn deprecated @npmcli/[email protected]: This functionality has been moved to @npmcli/fs
npm warn deprecated [email protected]: This module is not supported, and leaks memory. Do not use it. Check out lru-cache if you want a good and tested way to coalesce async requests by a key value, which is much more comprehensive and powerful.
npm warn deprecated [email protected]: This package is no longer supported.
npm warn deprecated [email protected]: This package is no longer supported.
npm warn deprecated [email protected]: Rimraf versions prior to v4 are no longer supported
npm warn deprecated [email protected]: This package is no longer supported.
npm warn deprecated [email protected]: This package is no longer supported.
npm warn deprecated [email protected]: Glob versions prior to v9 are no longer supported
npm warn deprecated [email protected]: This package is no longer supported.
npm warn deprecated [email protected]: This package is no longer supported.
Failed to connect to MCP server:  McpError: MCP error -32000: Connection closed
    at Client._onclose (file:///Users/bdmorin/.npm/_npx/c3ac9bf2b1e69376/node_modules/@modelcontextprotocol/sdk/dist/esm/shared/protocol.js:94:23)
    at _transport.onclose (file:///Users/bdmorin/.npm/_npx/c3ac9bf2b1e69376/node_modules/@modelcontextprotocol/sdk/dist/esm/shared/protocol.js:69:18)
    at ChildProcess.<anonymous> (file:///Users/bdmorin/.npm/_npx/c3ac9bf2b1e69376/node_modules/@modelcontextprotocol/sdk/dist/esm/client/stdio.js:85:77)
    at ChildProcess.emit (node:events:507:28)
    at maybeClose (node:internal/child_process:1101:16)
    at ChildProcess._handle.onexit (node:internal/child_process:305:5) {
  code: -32000,
  data: undefined
}
Failed to connect to server npx -y @supabase/mcp-server-supabase@latest --access-token sbp_93cf52ac8a0a94277fa28e670c4cf744dc418cd8
McpError: MCP error -32000: Connection closed
    at Client._onclose (file:///Users/bdmorin/.npm/_npx/c3ac9bf2b1e69376/node_modules/@modelcontextprotocol/sdk/dist/esm/shared/protocol.js:94:23)
    at _transport.onclose (file:///Users/bdmorin/.npm/_npx/c3ac9bf2b1e69376/node_modules/@modelcontextprotocol/sdk/dist/esm/shared/protocol.js:69:18)
    at ChildProcess.<anonymous> (file:///Users/bdmorin/.npm/_npx/c3ac9bf2b1e69376/node_modules/@modelcontextprotocol/sdk/dist/esm/client/stdio.js:85:77)
    at ChildProcess.emit (node:events:507:28)
    at maybeClose (node:internal/child_process:1101:16)
    at ChildProcess._handle.onexit (node:internal/child_process:305:5) {
  code: -32000,
  data: undefined
}
node:internal/process/promises:394
    triggerUncaughtException(err, true /* fromPromise */);
    ^

McpError: MCP error -32000: Connection closed
    at Client._onclose (file:///Users/bdmorin/.npm/_npx/c3ac9bf2b1e69376/node_modules/@modelcontextprotocol/sdk/dist/esm/shared/protocol.js:94:23)
    at _transport.onclose (file:///Users/bdmorin/.npm/_npx/c3ac9bf2b1e69376/node_modules/@modelcontextprotocol/sdk/dist/esm/shared/protocol.js:69:18)
    at ChildProcess.<anonymous> (file:///Users/bdmorin/.npm/_npx/c3ac9bf2b1e69376/node_modules/@modelcontextprotocol/sdk/dist/esm/client/stdio.js:85:77)
    at ChildProcess.emit (node:events:507:28)
    at maybeClose (node:internal/child_process:1101:16)
    at ChildProcess._handle.onexit (node:internal/child_process:305:5) {
  code: -32000,
  data: undefined
}

Node.js v23.11.0

I'm not a node dev, so I asked gpt.

Yeah, I can help make sense of this.

⸻

🧵 What’s Happening

You’re running npm i in a Supabase-related repo, and it’s trying to install @supabase/sql-to-rest, which depends on libpg-query, a native Node addon. The failure is happening while compiling the C source for that native dependency.

⸻

🧨 The Actual Failure

This is the root error:

src/postgres/src_port_snprintf.c:374:1: error: static declaration of 'strchrnul' follows non-static declaration

That means:
	•	libpg-query defines a static strchrnul() function.
	•	But your macOS SDK already declares strchrnul() non-statically in /usr/include/_string.h.
	•	This is a conflict between the Postgres vendored C code and your macOS SDK.

Additionally:

warning: 'strchrnul' is only available on macOS 15.4 or newer [-Wunguarded-availability-new]

So you’re on macOS 15.4+, but the build is targeting macOS 10.7, so the compiler thinks strchrnul() isn’t safe to use directly.

⸻

💣 Why It’s Failing

You’re on:
	•	macOS 15.4
	•	Apple Silicon (arm64)
	•	Node 23.11.0 (latest)
	•	node-gyp 11.0.0

But libpg-query:
	1.	Doesn’t have a prebuilt binary for node-v131 (Node 23 ABI) and macOS arm64.
	2.	Falls back to source compilation.
	3.	Triggers a C standard library conflict during compilation.

⸻

✅ Fixes & Workarounds

1. Patch the C source

Edit src/postgres/src_port_snprintf.c to avoid redefining strchrnul if it’s already defined:

#ifndef HAVE_STRCHRNUL
static const char *strchrnul(const char *s, int c) {
  while (*s && *s != c) s++;
  return s;
}
#endif

Or protect it with a version check or macro. This is the cleanest path forward if you’re comfortable patching.

⸻

2. Use an older Node version

Try downgrading to Node 20 or 18, which are LTS and may still have prebuilt libpg-query binaries:

nvm install 20
nvm use 20

Then reinstall:

rm -rf node_modules package-lock.json
npm i



⸻

3. Set a higher macOS deployment target

Override the deployment target to match your actual macOS version to silence the strchrnul availability errors:

export MACOSX_DEPLOYMENT_TARGET=15.4
npm i

But this won’t fix the core strchrnul conflict unless it’s conditionally compiled.

⸻

4. File a PR or issue

If you’re using the latest libpg-query, this is probably something upstream should fix to support C23 and modern macOS SDKs cleanly.

GitHub: https://github.com/supabase/libpg-query

⸻

Let me know if you want a quick patch script or want to try the Node downgrade route and need help setting it up.

again, I have no idea what's the right move here.

I failed to get this to work in claude desktop, cline, and locally debugging.

[tracyscott]

Try overriding the broken libpg-query dependency that is being picked up from the Supabase dependency. I was able to get it running with node 20 and forcing a newer libpg-query dependency. Technically not correct until Supabase itself is fixed up but I was able to get it running to play around with it on Windows. I had the exact same compilation failure.

More details:
#31

[bdmorin]

Thanks, I'll give this a shot.