---
phase: 94-subprocess-error-contracts
plan: 01
type: execute
wave: 1
depends_on:
  - v1.53-milestone-close
files_modified:
  - research/knowledge-hub/tests/test_subprocess_error_contracts.py
autonomous: true
requirements:
  - REQ-ERR-01
  - REQ-ERR-02
---

<objective>
Lock the subprocess failure contract so operator-facing errors keep command and
return-code context.
</objective>
