[engine-failure] PROJ-823-llmxive-follow-up-extending-multabench-b @ tasks: RuntimeError

Automated report (spec 023 / FR-016) — an unexpected engine failure occurred while processing **PROJ-823-llmxive-follow-up-extending-multabench-b** at stage `tasks`.

```
RuntimeError: LLMReviewer[coverage]: 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: coverage\nreviewer_kind: llm\nstage: tasked\nartifact_path: projects/PROJ-823-llmxive-follow-up-extending-multabench-b/specs/001-llmxive-follow-up-extending-multabench-b/tasks.'
```

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 by tracing the `tasks` stage and `LLMReviewer[coverage]` handling for project PROJ-823-llmxive-follow-up-extending-multabench-b, using the reported frontmatter excerpt as the reproduction case. Run the normal retry cadence and verify that the truncated review is rejected without preventing the project from remaining schedulable.

Written by the indexing model from the issue text.