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phases/5-markdown-rendering-assets/step2.md

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+# Step 2: figure-asset-writer
+
+## Read First
+- /AGENTS.md
+- /PLAN.md
+- /PROGRESS.md
+- /docs/HARNESS.md
+- /docs/IMPLEMENTATION_PLAN.md
+- /docs/ARCHITECTURE.md
+- /docs/CONVERSION_POLICY.md
+- /phases/1-core-runtime-contracts/step2.md
+- /phases/5-markdown-rendering-assets/step0.md
+
+## Task
+Implement deterministic image/figure asset writing and Markdown image reference generation.
+
+Use hash-based deduplication when asset bytes are available and preserve figure captions and reference anchors.
+
+## Sprint Contract
+- Done means: figure assets can be written to temp output bundles with deterministic names and Markdown references.
+- Hard thresholds: duplicate images share stored assets where configured; Korean path output is tested; missing assets produce validation failures, not broken silent links.
+- Files owned: `src/pdftomd/assets.py`, renderer integration/tests, `PROGRESS.md`, phase index.
+- Dependencies: Output bundle contract and renderer.
+
+## Acceptance Criteria
+```powershell
+python scripts\validate_workspace.py
+.\venv\python.exe -m pytest tests
+```
+
+## Verification
+1. Run the acceptance commands.
+2. Confirm tests write only to temporary directories.
+3. Update `PROGRESS.md` and this phase index.
+
+## Do Not
+- Do not write into real `output/` during tests.
+- Do not rename source PDFs.
+- Do not drop figure captions.