Root cause: modelName was 'deepseek-chat' in early Definition draft.
Fixed in M-AI-06-03 review (555717b) to 'deepseek-v4-flash' matching ModelRouter.
GATE doc P2-01 was stale — updated to reflect resolved status.
No actual model routing change occurred.
Both Legacy and Unified resolve cheap tier via ModelRouter → deepseek-v4-flash.
Co-Authored-By: Claude <noreply@anthropic.com>