PDFToMD/phases/6-cli-runtime-resume/step3.md

Step 3: device-oom-policy

Read First

• /AGENTS.md
• /PLAN.md
• /PROGRESS.md
• /docs/HARNESS.md
• /docs/IMPLEMENTATION_PLAN.md
• /docs/ARCHITECTURE.md
• /docs/CONVERSION_POLICY.md
• /docs/TOOLCHAIN.md
• /phases/1-core-runtime-contracts/step1.md

Task

Implement runtime device selection, CUDA fail-fast behavior, auto CPU fallback behavior, and OOM retry policy hooks.

This step should be tested with mocks and small CUDA smoke checks only where safe.

Sprint Contract

• Done means: runtime policy enforces explicit CUDA fail-fast, auto fallback warning, and configurable OOM retry reductions.
• Hard thresholds: no silent CPU fallback for explicit CUDA; tests do not require exhausting VRAM; GTX 1070 Ti constraints remain documented.
• Files owned: src/pdftomd/runtime.py, tests, docs/TOOLCHAIN.md if behavior changes, PROGRESS.md, phase index.
• Dependencies: Runtime config options.

Acceptance Criteria

python scripts\validate_workspace.py
.\venv\python.exe -m pytest tests

Verification

1. Run the acceptance commands.
2. Confirm CUDA smoke test instructions still work separately.
3. Update PROGRESS.md and this phase index.

Do Not

• Do not intentionally trigger real GPU OOM in tests.
• Do not change PyTorch pins without updating docs/TOOLCHAIN.md.
• Do not hide runtime warnings.