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.

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 or AGENTS.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:

• List component directories to understand organization
• Search for test file patterns (e.g., *.test.*, *_test.*, test_*)
• List utility directories to see how helpers are organized

Naming Patterns:

• Search for exported function declarations to identify naming style
• Search for class declarations to identify class naming style

Import Patterns:

• Search for import statements to identify absolute vs relative import styles

Step 3: Similar Features

Find features similar to what you're building:

1. Search for similar functionality:

• Search for files and content matching the feature you are implementing

1. Study the implementation:

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

1. Note the patterns:

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

Common Convention Areas

Naming Conventions

Discover by example:

• Search for function declarations, variable declarations, and component names in the source directory

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:

• List files in component or feature directories to see how they are organized

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 for try-catch patterns, custom error types, and error handling in API layers

Apply what you find:

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

Testing Patterns

Discover the pattern:

• Read the first 50 lines of existing test files to understand test structure
• Check for test setup files and 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 for fetch/axios/api usage patterns
• Read API response handling functions

Match the patterns:

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

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

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

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 systematic discovery and application of project-specific conventions by examining config files, existing code patterns, and similar features in the codebase.

Capabilities needed: File reading, file search (by pattern and content), directory listing.

Adaptation guidance: This is a methodology skill that describes a convention discovery process. The search techniques described (listing directories, searching for patterns, reading files) should be mapped to whatever file access capabilities the host platform provides. No platform-specific tool calls are embedded.

Configurable parameters: None.