• Claude Code v2.1.71
  • No statusLine configured
• next-devtools-mcp 0.3.10
• next 16.1.6
• macOS Sequoia 15.7.4
• Apple M1 Pro

Everything works correctly. Claude reports (/mcp)

next-devtools · ✔️ connected

After prompting to make sure, Claude reports

The ... dev server is running on port 4200, and the next-devtools MCP connected successfully.

However when exiting Claude (e.g. with /exit), it consistently reports

1 MCP server failed

With this being the only MCP server configured.

Asking Claude to diagnose, it reports

This is a cosmetic issue, not a real problem. When Claude Code exits, it sends a shutdown signal to any MCP server subprocesses it manages. The next-devtools MCP server (running on port 4200) likely exits with a non-zero code when it receives that signal — which Claude Code reports as "failed."

The actual Next.js dev server process continues running fine; only the MCP sidecar connection is torn down.

Why it happens: MCP servers started by Claude Code are treated as managed subprocesses. On exit, Claude sends SIGTERM and waits briefly. If the process exits with a non-zero status (common for servers that don't handle SIGTERM gracefully), it's counted as a failure.

Is it a problem? No. The ... dev server on port 4200 is unaffected. The message is just Claude Code reporting that the MCP subprocess didn't exit cleanly.

To suppress it: You'd need the next-devtools package to handle SIGTERM and exit with code 0 — that's an upstream fix in the mcp__next-devtools package, not something you can easily configure from Claude Code's side.

This is not critical, but seeing that red "failed" error every time activates my inner "something is wrong" system.