# Step 2: syntax-diagnostics

## Read First

Read these files before editing:

- `/AGENTS.md`
- `/docs/ARCHITECTURE.md`
- `/docs/ADR.md`
- `/docs/io-definitions/abaqus-input-parser-io.md`
- `/src/fesa/io/abaqus/input_parser.hpp`
- `/src/fesa/io/abaqus/input_parser.cpp`
- `/tests/unit/abaqus_input_parser_mesh_test.cpp`

Review completed step summaries in `/phases/abaqus-input-parser/index.json`.

## Task

Add structured diagnostics for parser syntax and unsupported subset behavior.

Required behavior:

- Unsupported keywords produce `Status::is_ok() == false` with an error
  diagnostic code and message that identifies the keyword.
- Malformed `*NODE` and `*ELEMENT` data lines produce error diagnostics.
- Missing required `TYPE` on `*ELEMENT` produces an error diagnostic.
- Unsupported element types produce an error diagnostic and do not add that
  element.
- Diagnostics must include enough context in the message to locate the line
  number.
- Existing valid mesh parser behavior remains unchanged.

## Tests To Write First

Extend `/tests/unit/abaqus_input_parser_mesh_test.cpp` or add
`/tests/unit/abaqus_input_parser_diagnostics_test.cpp` before production code.

Test:

- unsupported keyword failure;
- malformed node row failure;
- missing element `TYPE` failure;
- unsupported element type failure.

Run the targeted CTest and confirm the new tests fail for missing behavior
before implementation.

## Acceptance Criteria

```powershell
ctest --test-dir build/msvc-debug --output-on-failure -C Debug -R abaqus_input_parser
python -m unittest discover -s scripts -p "test_*.py"
python scripts/validate_workspace.py
```

## Verification Procedure

Update step 2 status with summary or a concrete error/blocked reason.

## Forbidden

- Do not add new semantic model fields except what diagnostics require.
- Do not add material, section, step, boundary, or load parsing.