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

.agents/rules/code-idioms-and-conventions.md

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+---
+trigger: always_on
+---
+
+## Code Idioms and Conventions
+
+### Universal Principle
+
+**Write idiomatic code for the target language:**
+
+- Code should look natural to developers familiar with that language  
+- Follow established community conventions, not personal preferences  
+- Use language built-ins and standard library effectively  
+- Apply language-appropriate patterns (don't force patterns from other languages)
+
+### Idiomatic Code Characteristics
+
+- Leverages language features (don't avoid features unnecessarily)  
+- Follows language naming conventions  
+- Uses appropriate error handling for language (exceptions vs Result types)  
+- Applies established community patterns
+
+### Avoid Cross-Language Anti-Patterns
+
+- ❌ Don't write "Java in Python" or "C in Go"  
+- ❌ Don't force OOP patterns in functional languages  
+- ❌ Don't avoid language features because they're "unfamiliar"  
+- ✅ Learn and apply language-specific idioms
+
+### Language-Specific Idioms
+
+This file defines the universal principle. Each language has a dedicated file with concrete patterns, tooling choices, and idiom-specific rules. **Load the relevant file when working in that language** — it is the authoritative source for that ecosystem.
+
+| Language / Framework | Idiom File                         | When to Load                                    |
+| -------------------- | ---------------------------------- | ----------------------------------------------- |
+| **Go**               | @go-idioms-and-patterns.md         | Go services, APIs, CLI tools                    |
+| **TypeScript**       | @typescript-idioms-and-patterns.md | Any TypeScript project (backend, frontend, CLI) |
+| **Vue 3**            | @vue-idioms-and-patterns.md        | Vue components, Pinia stores, composables       |
+| **Flutter / Dart**   | @flutter-idioms-and-patterns.md    | Mobile apps, Flutter widgets, Riverpod          |
+| **Rust**             | @rust-idioms-and-patterns.md       | Rust binaries, libraries, workspaces            |
+
+> Each language-specific file is independently changeable. It governs only its own ecosystem's coding idioms and defers to the relevant cross-cutting principle files (error handling, testing, logging, etc.) for universal guidance.
+
+### Related Principles
+- Core Design Principles @core-design-principles.md
+- Code Completion Mandate @code-completion-mandate.md