Fails with "posix_spawnp failed" and then misdiagnoses command as missing

[spqw]

Describe the bug

GitHub Copilot CLI fails to launch a shell command with:

<exited with error: posix_spawnp failed.>

After that, the agent may incorrectly conclude that the command is not installed or not on PATH, even when the command exists and runs normally outside Copilot.

Environment

• Copilot CLI: 1.0.27
• macOS: 26.4 (25E246)
• Architecture: arm64
• Terminal: Reproduced in Ghostty and Terminal app

Expected behavior

Copilot should either:

• run the shell command successfully, or
• report a shell/process-launch failure without inferring that the command is missing.

It should not translate posix_spawnp failed into “command not found” unless it has separately verified that.

Actual behavior

Copilot returns:

  <exited with error: posix_spawnp failed.>

and then incorrectly infers that the command is unavailable or not on PATH.

Reproduction

Prompt used:

  Run exactly: command -v teamcity && teamcity auth status. Do not explain, just use the shell tool and report the result.

Observed results

1. Direct shell outside Copilot

This succeeds:

  command -v teamcity && teamcity auth status

Output begins with:

/opt/homebrew/bin/teamcity

and the authentication status is reported correctly.

2. Copilot non-interactive without broad approval

Command:

  copilot -p "Run exactly: command -v teamcity && teamcity auth status. Do not explain, just use the shell tool and report the result."

Result:

Permission denied and could not request permission from user

That is understandable for non-interactive permissions.

3. Copilot non-interactive with broad approval

Command:

  copilot -p "Run exactly: command -v teamcity && teamcity auth status. Do not explain, just use the shell tool and report the result." --allow-all-tools

Result:

Why this looks like a CLI bug

The same shell command works outside Copilot in the same environment.

This suggests:

1. a shell/process-launch failure inside Copilot CLI, and
2. a reasoning/diagnostic bug where posix_spawnp failed is treated as if the command were missing from PATH.

Affected version

1.0.27

Steps to reproduce the behavior

brew install jetbrains/utils/teamcity
copilot -p "Run exactly: command -v teamcity && teamcity auth status. Do not explain, just use the shell tool and report the result."

Expected behavior

No response

Additional context

No response