kent-beck-review

# Kent Beck Code Review Lens > "Make the change easy, then make the easy change." ## Four Rules of Simple Design (in priority order) 1. **Passes tests** — Tests pass 2. **Reveals intention** — Names and structure reveal intent 3. **No duplication** — Eliminate idea-level duplication 4. **Fewest elements** — Minimal components ## Review Checklist ### File Size ```bash # Detect 500+ line files (God Object candidates) find core/ -name "*.py" -exec wc -l {} + | sort -rn | head -20 ``` File size identifies inspection candidates, not a split requirement. Trace responsibilities, callers, and reasons to change before proposing extraction. Do not carry a dated file-size snapshot forward as current implementation status. ### Method Size & Complexity Inspect the actual function and its callers. Function length, nesting, and branch counts do not by themselves justify a Strategy, dispatch table, or new module. Prefer an early return or an existing helper when it resolves the identified failure without obscuring domain behavior. ### Reveals Intention | Anti-pattern | Improvement | |-------------|-------------| | `def process(data)` | `def score_analyst_response(response)` | | `result = fn(x, y, z)` | Use meaningful variable names | | `# This function does X` | Reveal through function name, remove comment | | `magic number 0.7` | `CONFIDENCE_THRESHOLD = 0.7` | ### No Duplication Detect idea-level duplication (not just copy-paste but missing abstractions): Trace repeated decisions through their shared owner. Unify behavior that must change together; keep similar-looking paths separate when their contracts differ. Neither repetition count nor structural similarity alone requires a factory, Protocol, or generic abstraction. ### Fewest Elements | Unnecessary Element | Criteria | |--------------------|----------| | Unused parameters | Wrappers that only pass `**kwargs` | | ABC with single implementation | Check the substitution contract; a concrete class may be sufficient | | Empty `__init__.py` | Check package, distribution, discovery, and import contracts before removal | | Unused imports | Auto-detected by ruff F401 | ## Scope and Verification A review does not authorize refactoring. Follow the [workflow](../../../docs/workflow.md) for requested changes and the [deletion gate](../agent-anti-pattern/references/field-guide.md#deletion-gate) before removing code, tests, or package files. Use [verification gates](../geode-workflow/references/verification-gates.md) for targeted checks and evidence reuse. Report concrete findings with current file/line evidence; no finding is preferable to a speculative simplification.