Description
A Codex sub-agent gets its own transcript file linked by session_meta’s spawn block, with depth, agent path and nickname. sub_agent_activity and agent_message with author and recipient paths give the full multi-agent message graph, which nothing else in either ecosystem exposes.
Acceptance Criteria
- #1 Spawned sessions are linked to their parent by parent_thread_id with the recorded depth
- #2 sub_agent_activity produces spawn and completion items
- #3 agent_message populates direction from author and recipient, bounded to a small enum
- #4 Agent paths and thread ids stay record fields
- #5 Depth is bucketed for the metric dimension; the raw depth stays on the histogram and the record
Definition of Done
- #1 just check passes: fmt-check, lint, build, test-short, probe-ci, dashboard-check and docs-links all clean
Implementation Plan
Wave 1 lane 6: write focused tests first, implement Codex limits/agents/compaction only in the assigned files, and return any shared-helper requirement to root; root integrates and runs the final gate.
Final Summary
Codex parent/depth topology, activity, bounded message direction, and raw record fields are implemented; tests passed.