sessionStart hook in .github/hooks/ does not fire in Copilot CLI (v0.0.420) #1730

Describe the bug

sessionStart hooks defined in .github/hooks/*.json do not execute when starting a Copilot CLI session.

Environment

• CLI version: v0.0.420
• OS: Windows 11
• Shell: PowerShell 7

Hook configuration

File: .github/hooks/test-hook.json

{
  "version": 1,
  "hooks": {
    "sessionStart": [
      {
        "type": "command",
        "bash": "echo \"Session started: $(date)\" >> logs/session.log",
        "powershell": "Add-Content -Path logs/session.log -Value \"Session started: $(Get-Date)\"",
        "cwd": ".",
        "timeoutSec": 10
      }
    ]
  }
}

Expected behavior

logs/session.log should be created with a timestamp entry when a CLI session starts.

Actual behavior

logs/session.log is never created. The sessionStart hook does not fire.

Additional context