Project conventions

Project Conventions

This skill guides you in discovering and applying project-specific conventions. Every codebase has its own patterns and practices - your job is to find them and follow them.

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Convention Discovery Process

Step 1: Project Configuration

Check these files for explicit conventions:

Code Style:

• .eslintrc*, eslint.config.* - JavaScript/TypeScript linting rules
• .prettierrc*, prettier.config.* - Formatting rules
• pyproject.toml, setup.cfg, .flake8 - Python config
• .editorconfig - Editor settings
• ruff.toml, .ruff.toml - Ruff linter config

Project Structure:

• tsconfig.json - TypeScript paths and settings
• package.json - Scripts, dependencies
• pyproject.toml - Python project config

Documentation:

• CONTRIBUTING.md - Contribution guidelines
• CLAUDE.md - AI coding guidelines
• README.md - Project overview
• docs/ - Extended documentation

Step 2: Existing Code Patterns

Study the codebase to find implicit conventions:

File Organization:

# Find how components are organized
ls -la src/components/

# Search for test file patterns matching *.test.*, *_test.*, or test_*

# Find how utilities are organized
ls -la src/utils/ src/lib/ src/helpers/

Naming Patterns:

# Search file contents for exported function declarations
# Search file contents for Python function definitions
# Search file contents for exported class declarations
# Search file contents for Python class definitions

Import Patterns:

# Search file contents for import statements to detect absolute vs relative style

Step 3: Similar Features

Find features similar to what you're building:

1. Search for similar functionality:

   # If building a "user profile" feature
   # Search for files matching *profile* and content matching "profile"
   

2. Study the implementation:

   • How is it structured?
   • What patterns does it use?
   • How does it handle errors?
   • How is it tested?

3. Note the patterns:

   • Component structure
   • State management approach
   • API call patterns
   • Validation approach

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Common Convention Areas

Naming Conventions

Discover by example:

# Search file contents for function, variable, and component naming patterns

Common patterns:

• camelCase for functions/variables
• PascalCase for components/classes
• UPPER_SNAKE for constants
• kebab-case for file names (some projects)
• snake_case for file names (Python)

File Structure

Discover the pattern:

# Examine component and module directory layouts

Common patterns:

Flat structure:

components/
  Button.tsx
  Button.test.tsx
  Button.styles.ts

Folder per component:

components/
  Button/
    index.ts
    Button.tsx
    Button.test.tsx
    Button.module.css

Feature-based:

features/
  auth/
    components/
    hooks/
    api.ts
    types.ts

Error Handling

Discover the pattern:

# Search file contents for try-catch patterns, custom error types, and API error handling

Apply what you find:

• Use the same error types
• Follow the same handling pattern
• Match logging approach

Testing Patterns

Discover the pattern:

# Examine test file structure, setup files, and test utilities

Match the patterns:

• Test file location (co-located vs separate)
• Naming convention (*.test.ts vs *.spec.ts)
• Setup and teardown approach
• Mocking strategy
• Assertion style

API Patterns

Discover the pattern:

# Search file contents for API call patterns (fetch, axios, api references)
# Examine API response handling in service files

Match the patterns:

• How are endpoints defined?
• How is authentication handled?
• What's the error format?
• How are responses typed?

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Convention Application Checklist

When implementing a feature, verify you're following conventions for:

Code Style

• Variable naming matches existing code
• Function naming matches existing code
• File naming follows project pattern
• Import style matches (absolute vs relative)

Structure

• File location follows project structure
• Component organization matches
• Export style matches (default vs named)

Patterns

• Error handling follows project patterns
• Async patterns match existing code
• State management follows project approach
• API calls follow established patterns

Testing

• Test file location is correct
• Test naming follows convention
• Test structure matches existing tests
• Mocking approach is consistent

Documentation

• Comments follow existing style
• JSDoc/docstrings match project
• README updates if needed

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When Conventions Conflict

Sometimes you'll find inconsistent patterns:

1. Prefer newer code - Recent files often reflect current team preferences
2. Prefer maintained code - Active parts of the codebase reflect current practices
3. Prefer documented conventions - Explicit rules in configs override implicit patterns
4. Ask if unclear - When in doubt, ask the user which pattern to follow

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Red Flags

Watch for these signs that you might be breaking conventions:

• Your code looks very different from surrounding code
• You're using a library/pattern not used elsewhere
• Your file structure doesn't match siblings
• Your naming feels inconsistent with the codebase
• Linting errors (the project has explicit rules you're breaking)

When you notice these, stop and investigate the existing conventions more carefully.

Integration Notes

What this component does: Guides the discovery and application of project-specific conventions to ensure new code matches existing patterns and practices.

Capabilities needed:

• File reading (to examine existing code and config files)
• File search (to discover project structure and naming patterns)
• Content search (to find coding patterns in existing files)

Adaptation guidance:

• This is a reference/knowledge skill with no orchestration logic — it works on any platform as-is
• The bash examples are illustrative; adapt search commands to whatever tooling is available in the target harness