---
name: abaqus-subroutine-numerical-review
description: Use when independently reviewing Abaqus User Subroutine formulation correctness, algorithmic consistency, tangent consistency, state updates, stability risks, patch tests, locking, Jacobian handling, and implementation readiness.
---

# Abaqus Subroutine Numerical Review

Use this skill to review whether a formulation is numerically sound enough for Abaqus User Subroutine interface definition and Fortran implementation planning. Numerical review is the owned artifact for this skill.

## Inputs

Read first:

- `AGENTS.md`
- `docs/ABAQUS_SUBROUTINE_AGENT_DESIGN.md`
- `docs/numerical-reviews/README.md`
- `docs/formulations/<feature-id>-formulation.md`
- Related requirements and research documents

## Workflow

1. Check dimensional consistency, units, coordinate conventions, and sign conventions.
2. Check residual, stress update, and consistent tangent consistency.
3. Check kinematics, Jacobian mapping, integration order, state variable update, and output recovery.
4. Identify rigid body modes, patch test expectations, finite-difference tangent check needs, locking, hourglass, singular Jacobian, conditioning, and convergence risks.
5. Require revisions when the formulation is ambiguous or inconsistent.
6. Return a verdict: `pass-for-interface-definition`, `pass-for-implementation-planning`, `needs-formulation-revision`, `needs-research`, or `blocked`.

## Output Contract

Produce or revise `docs/numerical-reviews/<feature-id>-review.md` with Review Verdict, Critical Findings, Numerical Risk Assessment, Consistency Checks, Verification Readiness, Required Revisions, and Downstream Handoff.

## Boundaries

- Do not implement code.
- Do not edit formulations directly.
- Do not design Fortran source layout.
- Do not run Abaqus.
- Do not generate reference CSVs.
- Do not approve release readiness.

## Quality Gate

- Findings cite the exact formulation section or missing assumption.
- Tangent/stiffness expectations are explicit enough for tests.
- Patch test, finite-difference tangent check, and singular case expectations are documented.
- Blocking issues are routed to the owning upstream agent.

## Handoff

Send approved formulations to I/O Definition Agent and Implementation Planning Agent. Send defects back to Formulation Agent with exact correction requests.