According to: https://code.claude.com/docs/en/hooks
SessionStart hooks receive source, model, and optionally agent_type

See also https://github.com/microsoft/vscode/blob/d9b443da371e75096580a61a061d80f46d0febef/extensions/copilot/src/extension/intents/node/toolCallingLoop.ts

@pwang347 - Do you know why it is missing? Sub agent has it.

Issue should be easy to fix as the model and agent name are already referenced in this file (see the run function)

• Copilot Chat Extension Version:: 0.44.2026040901
• VS Code Version: 1.116.0-insider
• OS Version: Win11
• Feature (e.g. agent/edit/ask mode): all
• Selected model (e.g. GPT 4.1, Claude 3.7 Sonnet): all
• Logs:
  2026-04-13 08:18:56.535 [info] [gulp-symdest does not preserve links on electron #2] [SessionStart] Running: {"command":"node hooks.js SessionStart","cwd":{"$mid":1,"fsPath":"c:\repos\","_sep":1,"external":"file:///c%3A/repos/","path":"/c:/repos/","scheme":"file"},"timeout":30}
  2026-04-13 08:18:56.535 [info] [gulp-symdest does not preserve links on electron #2] [SessionStart] Input: {"timestamp":"2026-04-13T15:18:56.490Z","hook_event_name":"SessionStart","session_id":"20426ce9-02f7-424c-bc7e-e40e817a9443","transcript_path":"c:\Users\\AppData\Roaming\Code - Insiders\User\workspaceStorage\50161c4801cda5d1cc798632bcdaef21\GitHub.copilot-chat\transcripts\20426ce9-02f7-424c-bc7e-e40e817a9443.jsonl","source":"new","cwd":"c:\repos\****"}

Steps to Reproduce:

1. Configure a SessionStart hook
2. View in the output for the hooks