handoff compaction leaks <behavioral_directive> from spawn prompts into parent context

[worldofgeese]

Bug

After handoff compaction, <behavioral_directive> blocks injected by spawn into child agent prompts leak into the parent orchestrator session. This causes the parent to believe it is a child agent and refuse orchestration duties.

Root cause

spawn/index.ts:229 injects:

You are a focused child agent spawned by a parent agent...

into child prompts via a <behavioral_directive> wrapper.

When the parent session later calls handoff, handoff/compact.ts compacts the full conversation history — including the spawn prompt text that contained this directive. The compacted output preserves the <behavioral_directive> tag verbatim, promoting it to system-level context in the new clean window.

Reproduction

1. Parent orchestrator spawns a child agent
2. Child completes, result returns to parent
3. Parent calls handoff (or auto-compaction triggers)
4. Post-compaction, parent session now has <behavioral_directive>You are a focused child agent...</behavioral_directive> in its context
5. Parent refuses to orchestrate, claiming it cannot spawn further children

Expected behavior

handoff/compact.ts should strip <behavioral_directive> blocks from the session history before/during compaction. These are transient injection markers for child sessions, not durable parent state.

Workaround

None clean — user must start a new session after the leak occurs.

Environment

• pi 0.78.0
• pi-agenticoding (latest as of 2026-05-31)

[ofriw]

Thank you for reporting this issue! What model and provider do you see this happening with?

[worldofgeese]

Thanks for making this! openai-codex/gpt5-5. I have subagents running cursor/composer-2-5 but it's the main (gpt-5-5) session that gets polluted during handover rounds

[ofriw]

Thanks for making this! openai-codex/gpt5-5. I have subagents running cursor/composer-2-5 but it's the main (gpt-5-5) session that gets polluted during handover rounds

Happy you like it! What sub agents are you using? Does this happen with the spawn tool of this extension or some other sub agent implementation?