# Plan 02-01 Summary: Pydantic Entity Models
## What was done
1. **Fixed TYPE_CHECKING guards** — `datetime` in `components.py` and `ComponentType` in `graph.py` were behind `TYPE_CHECKING` blocks, which breaks Pydantic runtime model resolution when `from __future__ import annotations` is active. Moved to runtime imports with `# noqa: TC003/TC001` to suppress ruff's TCH rules (correct: Pydantic needs these at runtime).
2. **Dependencies verified** — `gitpython>=3.1.44`, `rapidfuzz>=3.14`, `python-frontmatter>=1.1` all importable (were already in pyproject.toml from Phase 1).
3. **Created `tests/test_entities.py`** — 11 test cases covering:
- ComponentType enum values (7 types, all lowercase strings)
- ComponentMetadata creation with all fields + round-trip serialization
- Default values for optional fields
- `generate_id()` deterministic ID generation
- Special character normalization in IDs (spaces, mixed case, whitespace)
- Frozen model immutability (raises ValidationError on mutation)
- `model_copy(update={})` produces new instance without modifying original
- ID field validator normalization
- GraphNode creation
- GraphEdge creation with EdgeType
- EdgeType enum values (5 types)
## Verification results
- **pytest**: 11/11 passed (0.22s)
- **pyright strict**: 0 errors, 0 warnings
- **ruff**: All checks passed
- **Integration**: All 5 entity types importable from `skill_retriever.entities`
## Files modified
| File | Change |
|------|--------|
| `src/skill_retriever/entities/components.py` | Moved `datetime` import out of TYPE_CHECKING |
| `src/skill_retriever/entities/graph.py` | Moved `ComponentType` import out of TYPE_CHECKING |
| `tests/test_entities.py` | **New** — 11 entity model tests |
## Decisions
- Used `# noqa: TC003/TC001` rather than `model_rebuild()` — simpler, keeps imports explicit, and correctly documents that Pydantic needs these at runtime despite `from __future__ import annotations`.
