56d7ade626
Closes brain-retro 2026-05-20 #12 — each Agent tool_use produces a subagent_invoked event with subagent_type / model (if explicit) / first 80 chars of description. Visibility from parent Claude's perspective; full subagent trace lives in subagents/ directory and is out of scope for this parser. 6 new vitest tests, 315/315 GREEN. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>