mvanhorn/last30days-skill · error

engine: subprocess exited with code %d

Error message

engine: subprocess exited with code %d

What it means

Error "engine: subprocess exited with code %d" thrown in mvanhorn/last30days-skill.

Source

Thrown at mcp/internal/engine/run.go:111

	err = cmd.Run()
	res := &RunResult{
		Stdout:   stdout.Bytes(),
		Stderr:   stderr.Bytes(),
		ExitCode: 0,
		TimedOut: errors.Is(subCtx.Err(), context.DeadlineExceeded),
	}
	if err == nil {
		return res, nil
	}

	var exitErr *exec.ExitError
	if errors.As(err, &exitErr) {
		res.ExitCode = exitErr.ExitCode()
		if res.TimedOut {
			return res, fmt.Errorf("engine: subprocess exceeded %s timeout", timeout)
		}
		return res, fmt.Errorf("engine: subprocess exited with code %d", res.ExitCode)
	}
	return res, fmt.Errorf("engine: subprocess failed to start: %w", err)
}

// resolvePython returns an absolute path to the interpreter or an error
// naming the install URL. If the caller supplied a path we trust it - tests
// rely on this to inject a stub. Otherwise we look up python3 on PATH.
func resolvePython(override string) (string, error) {
	if override != "" {
		return override, nil
	}
	path, err := exec.LookPath(DefaultPythonBinary)
	if err == nil {
		return path, nil
	}
	return "", fmt.Errorf(
		"engine: %s not found on PATH (need Python %s+, install from %s; current GOOS=%s)",
		DefaultPythonBinary, MinPythonVersion, PythonInstallURL, runtime.GOOS,

View on GitHub (pinned to c7460f6114)

Solutions

1. Read the subprocess stderr in the RunResult for the underlying Python error and fix that root cause.
2. Run last30days.py directly with the same arguments to reproduce and debug the non-zero exit.
3. Check that required API keys/config for the requested sources are present in the environment.

When it happens

Trigger: Fires when the last30days.py subprocess exits with a non-zero status. Inspect the captured stderr from the engine for the underlying Python error (missing keys, bad flags, source failures).

Common situations: See trigger scenarios.

AI-assisted analysis of mvanhorn/last30days-skill@c7460f6114 (2026-08-15). Data as JSON: /api/errors/5674115b6fd8785b. Report an issue: GitHub.