mirror of
https://github.com/openai/codex.git
synced 2026-05-22 20:14:17 +00:00
# What <img width="1792" height="1024" alt="image" src="https://github.com/user-attachments/assets/8f81d232-5813-4994-a61d-e42a05a93a3e" /> `SubagentStop` runs when a thread-spawned subagent turn is about to finish. Thread-spawned subagents use `SubagentStop` instead of the normal root-agent `Stop` hook. Configured handlers match on `agent_type`. Hook input includes the normal stop fields plus: - `agent_id`: the child thread id. - `agent_type`: the resolved subagent type. - `agent_transcript_path`: the child subagent transcript path. - `transcript_path`: the parent thread transcript path. - `last_assistant_message`: the final assistant message from the child turn, when available. - `stop_hook_active`: `true` when the child is already continuing because an earlier stop-like hook blocked completion. `SubagentStop` shares the same completion-control semantics as `Stop`, scoped to the child turn: - No decision allows the child turn to finish. - `decision: "block"` with a non-empty `reason` records that reason as hook feedback and continues the child with that prompt. - `continue: false` stops the child turn. If `stopReason` is present, Codex surfaces it as the stop reason. # Lifecycle Scope Only thread-spawned subagents run `SubagentStop`. Internal/system subagents such as Review, Compact, MemoryConsolidation, and Other do not run normal `Stop` hooks and do not run `SubagentStop`. This avoids exposing synthetic matcher labels for internal implementation paths. # Stack 1. #22782: add `SubagentStart`. 2. This PR: add `SubagentStop`. 3. #22882: add subagent identity to normal hook inputs.