# Step 2: latex-validation-repair

## Read First
- /AGENTS.md
- /PLAN.md
- /PROGRESS.md
- /docs/HARNESS.md
- /docs/IMPLEMENTATION_PLAN.md
- /docs/CONVERSION_POLICY.md
- /phases/0-harness-foundation/step3.md
- /phases/3-formula-pipeline/step1.md

## Task
Implement LaTeX and Markdown math validation for formula outputs, plus explicit repair helpers for safe cases.

Validation should cover delimiter balance and common `\begin{...}` / `\end{...}` pairs.

## Sprint Contract
- Done means: formula output validation returns actionable diagnostics and tested repairs for narrow, deterministic cases.
- Hard thresholds: validation does not silently mutate math; unrepairable failures fall back to Marker text; delimiter tests include both inline and block math.
- Files owned: `src/pdftomd/formulas.py`, `src/pdftomd/quality.py`, tests, `PROGRESS.md`, phase index.
- Dependencies: Phase 0 quality gates and Step 1 Nougat adapter.

## Acceptance Criteria
```powershell
python scripts\validate_workspace.py
.\venv\python.exe -m pytest tests
```

## Verification
1. Run the acceptance commands.
2. Confirm broken delimiter and environment examples are covered.
3. Update `PROGRESS.md` and this phase index.

## Do Not
- Do not build a broad LaTeX parser from scratch.
- Do not use LLM repair.
- Do not hide validation failures.