[autoresearch] baseline: system prompt quality tests (5/5 passing)

.agents/rules/documentation-principles.md

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+---
+trigger: always_on
+---
+
+## Documentation Principles
+
+### Self-Documenting Code
+
+**Clear naming reduces need for comments:**
+
+- Code shows WHAT is happening  
+- Comments explain WHY it's done this way
+
+**When to comment:**
+
+- Complex business logic deserves explanation  
+- Non-obvious algorithms (explain approach)  
+- Workarounds for bugs (link to issue tracker)  
+- Performance optimizations (explain trade-offs)
+
+### Documentation Levels
+
+1. **Inline comments:** Explain WHY for complex code  
+2. **Function/method docs:** API contract (parameters, returns, errors)  
+3. **Module/package docs:** High-level purpose and usage  
+4. **README:** Setup, usage, examples  
+5. **Architecture docs:** System design, component interactions, use valid mermaid diagram
+
+### Related Principles
+- Core Design Principles @core-design-principles.md
+- Code Organization Principles @code-organization-principles.md