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/

# Find test file patterns
find . -name "*.test.*" -o -name "*_test.*" -o -name "test_*"

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

Naming Patterns:

# Find function naming patterns
grep -r "^export function" src/ | head -20
grep -r "^def " src/ | head -20

# Find class naming patterns
grep -r "^export class" src/ | head -20
grep -r "^class " src/*.py | head -20

Import Patterns:

# Find import style (absolute vs relative)
grep -r "^import" src/ | head -30
grep -r "^from \." src/*.py | head -20

Step 3: Similar Features

Find features similar to what you're building:

1. Search for similar functionality:

   # If building a "user profile" feature
   grep -r "profile" src/
   find . -name "*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:

# Function names
grep -E "^(export )?(async )?function " src/**/*.ts

# Variable names
grep -E "^(const|let|var) " src/**/*.ts

# Component names
grep -E "^(export )?function [A-Z]" src/**/*.tsx

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:

# Component structure
ls -la src/components/Button/

# Module structure
ls -la src/features/auth/

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:

# Find try-catch patterns
grep -A5 "try {" src/**/*.ts

# Find error types
grep -r "extends Error" src/

# Find error handling in API
grep -r "catch" src/api/

Apply what you find:

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

Testing Patterns

Discover the pattern:

# Find test structure
head -50 src/**/*.test.ts

# Find test utilities
cat src/test/setup.ts
cat src/test/utils.ts

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:

# Find API call patterns
grep -r "fetch\|axios\|api\." src/

# Find API response handling
grep -A10 "async function fetch" src/api/

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.