Common Patterns

1# Bad
2Review this code
3
4# Good
5Review src/auth/login.ts for:
61. Security vulnerabilities (especially injection attacks)
72. Error handling completeness
83. Input validation
9Provide specific line numbers for any issues found.

1# Bad
2Fix the bug
3
4# Good
5The login form at src/components/LoginForm.tsx throws
6"Cannot read property 'email' of undefined" when submitted
7with empty fields. The form should show validation errors
8instead of crashing.

1# Bad
2Refactor the entire authentication system
3
4# Good
5Let's refactor authentication step by step:
61. First, analyze the current auth implementation
72. Then, identify issues and improvement opportunities
83. Finally, implement changes one module at a time
9Start with step 1: analyze src/auth/ and summarize the current implementation.

1# Project Context
2
3## Overview
4[Brief description of what this project does]
5
6## Tech Stack
7- Frontend: [framework]
8- Backend: [framework]
9- Database: [database]
10- Infrastructure: [cloud/hosting]
11
12## Key Directories
13- `src/` - Main source code
14- `tests/` - Test files
15- `docs/` - Documentation
16- `scripts/` - Build and deployment scripts

1# Coding Standards
2
3## Style
4- Use TypeScript strict mode
5- Prefer const over let
6- Use async/await over callbacks
7- Maximum line length: 100 characters
8
9## Naming
10- Components: PascalCase (UserProfile.tsx)
11- Functions: camelCase (getUserById)
12- Constants: UPPER_SNAKE_CASE (MAX_RETRY_COUNT)
13- Files: kebab-case (user-profile.tsx)
14
15## Testing
16- Unit tests required for utility functions
17- Integration tests for API endpoints
18- Use Jest and React Testing Library

1Review $1 for:
2
3## Security
4- [ ] Input validation
5- [ ] Authentication checks
6- [ ] Authorization checks
7- [ ] Injection vulnerabilities
8- [ ] Sensitive data exposure
9
10## Quality
11- [ ] Error handling
12- [ ] Edge cases
13- [ ] Code duplication
14- [ ] Complexity
15
16## Performance
17- [ ] N+1 queries
18- [ ] Unnecessary computations
19- [ ] Memory leaks
20
21Provide specific findings with line numbers.

1Generate tests for $1:
2
31. Identify all public functions and methods
42. For each function:
5   - Write happy path tests
6   - Write edge case tests
7   - Write error handling tests
83. Use Jest and follow existing test patterns
94. Run the tests and fix any failures
10
11Output the test file to the appropriate location.

1{
2  "name": "analyze",
3  "description": "Comprehensive codebase analysis",
4  "steps": [
5    {
6      "name": "inventory",
7      "prompt": "Create an inventory of all files and their purposes"
8    },
9    {
10      "name": "dependencies",
11      "prompt": "Map dependencies between modules",
12      "dependsOn": ["inventory"]
13    },
14    {
15      "name": "issues",
16      "prompt": "Identify potential issues and improvements",
17      "dependsOn": ["dependencies"]
18    },
19    {
20      "name": "report",
21      "prompt": "Generate a summary report",
22      "dependsOn": ["issues"],
23      "output": "ANALYSIS_REPORT.md"
24    }
25  ]
26}

1{
2  "name": "migrate",
3  "description": "Safe migration workflow",
4  "steps": [
5    {
6      "name": "backup",
7      "prompt": "Document current state before changes"
8    },
9    {
10      "name": "plan",
11      "prompt": "Create detailed migration plan",
12      "dependsOn": ["backup"]
13    },
14    {
15      "name": "implement",
16      "prompt": "Implement changes incrementally",
17      "dependsOn": ["plan"]
18    },
19    {
20      "name": "verify",
21      "prompt": "Verify changes and run tests",
22      "dependsOn": ["implement"]
23    }
24  ]
25}

1Before adding the new feature:
21. Search for similar implementations in the codebase
32. Understand the existing patterns
43. Follow the established conventions
54. Then implement the change

1If web-search fails:
21. Try searching local documentation
32. Check cached information in CLAUDE.md
43. Ask user for guidance

1# In CLAUDE.md
2
3## Error Handling
4When encountering errors:
51. Report the specific error message
62. Explain what was being attempted
73. Suggest potential solutions
84. Ask for guidance if unclear

1# Bad - Multiple tool calls
2Read file A, then read file B, then read file C
3
4# Good - Batched request
5Read files A, B, and C and summarize their relationships

1# Bad - Broad search
2Search for "error" in all files
3
4# Good - Targeted search
5Search for "AuthenticationError" in src/auth/