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phases/3-formula-pipeline/step1.md

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+# Step 1: nougat-command-adapter
+
+## Read First
+- /AGENTS.md
+- /PLAN.md
+- /PROGRESS.md
+- /docs/HARNESS.md
+- /docs/IMPLEMENTATION_PLAN.md
+- /docs/TOOLCHAIN.md
+- /docs/CONVERSION_POLICY.md
+- /phases/3-formula-pipeline/step0.md
+
+## Task
+Implement the Nougat formula-only adapter boundary.
+
+The adapter should accept formula candidates and return LaTeX candidates or structured failure results. It should support a configured Nougat command path and be mockable in unit tests.
+
+## Sprint Contract
+- Done means: Nougat execution is isolated behind a testable command adapter and never becomes the primary document parser.
+- Hard thresholds: failures preserve Marker fallback text; tests do not require GPU/model execution by default; command path handling works on Windows.
+- Files owned: `src/pdftomd/formulas.py`, optional `src/pdftomd/nougat_adapter.py`, tests, `PROGRESS.md`, phase index.
+- Dependencies: Step 0 formula candidates and Phase 1 options.
+
+## Acceptance Criteria
+```powershell
+python scripts\validate_workspace.py
+.\venv\python.exe -m pytest tests
+```
+
+## Verification
+1. Run the acceptance commands.
+2. Confirm `.\venv\Scripts\nougat.exe --help` remains documented as an environment check, not a unit-test requirement.
+3. Update `PROGRESS.md` and this phase index.
+
+## Do Not
+- Do not parse whole PDFs with Nougat.
+- Do not require model downloads for normal unit tests.
+- Do not discard Marker source text on failure.