[engine-failure] PROJ-943-llmxive-follow-up-extending-cosmos-3-omn @ tasks: RuntimeError

Automated report (spec 023 / FR-016) — an unexpected engine failure occurred while processing **PROJ-943-llmxive-follow-up-extending-cosmos-3-omn** at stage `tasks`.

```
RuntimeError: LLMReviewer[constraint_preservation]: review frontmatter has neither `verdict:` nor `concerns:`/`action_items:` — a contentless/truncated review MUST NOT count as acceptance (false-convergence guard). First 200 chars: '```yaml\n---\nreviewer_name: constraint_preservation\nreviewer_kind: llm\nstage: tasks\nartifact_path: projects/PROJ-943-llmxive-follow-up-extending-cosmos-3-omn/specs/001-llmxive-follow-up-extending-cosmo'
```

The project remains schedulable; it will retry on its normal cadence and recover once the underlying defect is fixed. Closing this issue does not require any project-state change.

Start with the automated report for PROJ-943 at the tasks stage and trace the LLMReviewer[constraint_preservation] path that parses the review frontmatter. Reproduce the truncated or contentless review failure and identify the relevant retry or validation entry point. Done means the underlying defect is fixed and the project can recover on its normal cadence without treating the review as acceptance.

Written by the indexing model from the issue text.