# Step 3: numerical-review

## Read These Files First

Read the following files before editing:

- `/AGENTS.md`
- `/docs/PRD.md`
- `/docs/ARCHITECTURE.md`
- `/docs/ADR.md`
- `/docs/requirements/euler-beam-3d.md`
- `/docs/research/euler-beam-3d-research.md`
- `/docs/formulations/euler-beam-3d-formulation.md`
- `/docs/numerical-reviews/README.md`

## Task

Create `/docs/numerical-reviews/euler-beam-3d-review.md`.

Review the formulation for implementation readiness. The review must include:

- dimension and units check for each stiffness coefficient
- symmetry and rigid body mode expectations
- local axis construction risks
- positive semi-definite local stiffness expectation before constraints
- test obligations before production code
- known numerical limits for slender beams and very small section constants
- pass/fail verdict for kernel implementation planning

If the formulation is not ready, mark the document status as `needs-upstream-decision` and update this phase step as blocked with a concrete reason.

Do not create C++ files in this step.

## Tests To Write First

- No C++ test is required in this documentation-only step.

## Acceptance Criteria

```powershell
python -m unittest discover -s scripts -p "test_*.py"
python scripts/validate_workspace.py
```

## Verification Notes

1. Confirm the review does not change requirements or formulation.
2. Confirm implementation-owned risks are turned into concrete tests.
3. Update `phases/euler-beam-3d/index.json` step 3:
   - success: `"status": "completed"`, `"summary": "3D Euler beam numerical review added"`
   - failure after retries: `"status": "error"`, `"error_message": "<specific error>"`
   - blocked: `"status": "blocked"`, `"blocked_reason": "<specific reason>"`

## Forbidden

- Do not modify requirements, formulation, source, tests, or reference artifacts.