The sub-agent briefing section told the model to "give the sub-agent
everything it needs" but never said which tools the sub-agent lacks or how
context actually reaches it — so briefings could ask the sub-agent to use
memory, spawn further agents, or switch profiles, all of which it can't.

- context_transfer: write the context the sub-agent needs (files, snippets,
  how to verify) into the scratchpad `context_transfer` section before
  spawning — it is injected automatically; the sub-agent does not inherit
  short-term memory or conversation history.
- Restricted toolset: the sub-agent has todo/scratchpad/reflect/filesystem/
  code_exec/terminal/list_tools but NOT memory/switch_profile/spawn_agent/
  schedule_recall/manage_recall — brief it to use only what it has (e.g.
  record findings in scratchpad, not memory).

The profile list is not duplicated — spawn_agent's own description carries it.

Co-Authored-By: Claude <noreply@anthropic.com>