[Agent · Phase 13] task_joiner

[jeremymanning]

Parent phase: #57

Purpose

Auto-spawned when every sibling sub-task succeeds; merges sub-task outputs into the parent task's expected artifact format.

What it produces / drives

Replaces the parent task's atomize.yaml with the merged artifact and ticks the parent task [X].

Dependencies

This agent depends on output from: task_atomizer

Acceptance criteria

• Only fires when ALL sibling sub-tasks succeed (failure → human escalation)
• Merged artifact validates against the parent task's contract

Manual test plan

1. Stage 3 sub-tasks all completed [X]
2. Run one step
3. Verify the parent task is now [X] and the merged artifact exists

Implementation pointer

• Registry entry: agents/registry.yaml → name: task_joiner
• Prompt: agents/prompts/task_joiner.md
• Code: search src/llmxive/ for the class