Claude Coding Prompts
Last updated: April 2026
I've tested hundreds of prompts with Claude for coding, and the difference between vague requests and precise instructions is staggering. Good prompts transform Claude from a generic assistant into your personal senior developer. These prompts were crafted through daily use—debugging production code, architecting systems, and refactoring legacy projects. Expect production-ready code, insightful architecture analysis, and explanations that actually make sense. I've filtered out what doesn't work to give you prompts that deliver immediate results.
Explain Code in Simple Terms
beginnerI need you to explain this [programming language] code to me as if I'm a beginner. Break down what each section does in plain English, not technical jargon. Focus on the overall purpose and how the different parts work together.
Here's the code:
```
[Paste your code here]
```Expected Output
Claude will produce a line-by-line breakdown in simple language, explaining the code's purpose, key functions, and data flow without assuming prior knowledge.
Generate Boilerplate Code
beginnerCreate a complete [programming language] file for a [type of component] with the following requirements:
- Must include proper imports/dependencies
- Include error handling for [specific edge cases]
- Follow [specific style guide, e.g., Google Style Guide]
- Add comprehensive comments explaining key decisions
Make the code production-ready and include a brief usage example at the bottom.Expected Output
Claude will generate a fully-formed code file with proper structure, error handling, comments, and a usage example showing how to implement the component.
Debug Error Message
beginnerI'm getting this error in my [programming language] code:
[Paste exact error message]
Here's the relevant code section:
```
[Paste 10-20 lines around where error occurs]
```
Explain what's causing this error in simple terms and provide 2-3 specific fixes. Rank the fixes from most to least likely to work based on common patterns.Expected Output
Claude will analyze the error, explain the root cause in plain language, and provide ranked solutions with code examples for each fix.
Convert Code Between Languages
beginnerConvert this [source language] code to [target language] while maintaining identical functionality. Preserve all logic, error handling, and comments. If there are language-specific idioms in [target language] that would improve the code, implement them and explain your changes in inline comments.
Source code:
```
[Paste code to convert]
```Expected Output
Claude will produce equivalent code in the target language with proper syntax, optimized idioms, and explanatory comments about any improvements made.
Refactor Legacy Code
intermediateRefactor this [programming language] code to improve readability and maintainability while preserving all functionality. Focus on:
1. Breaking down functions longer than [number] lines
2. Removing code duplication
3. Improving variable/function names
4. Adding proper error handling
5. Adding type hints/annotations where applicable
Provide the refactored code first, then a summary of changes made and why each improves the codebase.
Original code:
```
[Paste messy code here]
```Expected Output
Claude will return cleaned, modular code followed by a detailed changelog explaining each refactoring decision and its benefits.
Design System Architecture
intermediateAct as a senior software architect. Design a system for [system purpose] with the following constraints:
- Must handle [specific requirements, e.g., 10,000 concurrent users]
- Primary technology stack: [list technologies]
- Must integrate with [external systems]
- Budget/constraints: [any limitations]
Provide:
1. High-level architecture diagram (ASCII or description)
2. Component breakdown with responsibilities
3. Data flow description
4. Key design decisions and tradeoffs
5. Potential scaling bottlenecks and mitigation strategiesExpected Output
Claude will create a comprehensive system design with architecture overview, component specifications, data flow, and scaling considerations.
Write Comprehensive Tests
intermediateWrite complete test coverage for this [programming language] function/class. Include:
- Unit tests for all public methods
- Edge case tests
- Integration tests if applicable
- Mock external dependencies appropriately
- Use [testing framework, e.g., pytest, Jest]
Aim for 90%+ coverage of logical paths. Document what each test validates.
Code to test:
```
[Paste code here]
```Expected Output
Claude will generate a full test suite with organized test cases, proper mocking, edge case coverage, and documentation of test purposes.
Optimize Algorithm Performance
intermediateAnalyze this [programming language] algorithm for performance bottlenecks:
```
[Paste algorithm code]
```
Current time complexity: [if known, otherwise leave blank]
Provide:
1. Time and space complexity analysis
2. Identified bottlenecks with line numbers
3. 2-3 optimized versions with complexity improvements
4. Benchmark considerations for each version
5. Readability vs. performance tradeoff analysisExpected Output
Claude will analyze complexity, identify bottlenecks, provide optimized alternatives, and discuss tradeoffs between different optimization approaches.
Code Review Assistant
intermediatePerform a thorough code review on this [programming language] pull request. Focus on:
1. Security vulnerabilities
2. Performance issues
3. Code style violations (reference [style guide])
4. Testing gaps
5. Architecture concerns
6. Readability improvements
Structure your review as:
- Critical issues (must fix)
- Important suggestions (should fix)
- Minor nitpicks (could fix)
Code to review:
```
[Paste code diff or full code]
```Expected Output
Claude will provide a structured code review with prioritized issues, specific line references, and actionable improvement suggestions.
Chain-of-Thought Algorithm Design
advancedThink step by step like a computer scientist designing an algorithm for [problem description].
Constraints:
- Input: [describe input format and constraints]
- Output: [describe expected output]
- Time complexity target: [e.g., O(n log n)]
- Space complexity target: [e.g., O(1)]
Show your complete thinking process:
1. Restate the problem in your own words
2. Identify similar known algorithms
3. Design brute force solution
4. Optimize step-by-step
5. Handle edge cases
6. Write pseudocode
7. Analyze final complexity
Only after showing all reasoning, provide final [language] implementation.Expected Output
Claude will document its complete algorithmic thinking process before providing a final, optimized implementation with complexity analysis.
Legacy System Modernization Plan
advancedAct as a principal engineer tasked with modernizing this legacy [language] system. Current system overview:
[Describe current system, pain points, and business context]
Create a phased migration plan:
Phase 1: Assessment (2 weeks)
- Inventory and analysis tasks
- Risk assessment
Phase 2: Foundation (4 weeks)
- Infrastructure changes
- Testing strategy
Phase 3: Incremental migration (12 weeks)
- Feature-by-feature migration plan
- Rollback strategies
Phase 4: Decommissioning (2 weeks)
- Legacy shutdown procedure
Include concrete deliverables, success metrics, and team coordination requirements for each phase.Expected Output
Claude will generate a detailed, phased migration plan with timelines, deliverables, risk mitigation, and team coordination strategies.
Production Incident Simulation
advancedSimulate a production incident response for this [language/service] system. Incident description: [describe symptoms, e.g., "API latency increased 300%, error rate spiked to 15%"]
Role-play as the incident commander. Walk through:
1. Initial triage and severity assessment
2. Hypothesis generation (list 3-5 likely root causes)
3. Investigation steps with commands/queries to run
4. Mitigation strategies (immediate vs. long-term)
5. Communication plan for stakeholders
6. Post-mortem outline with preventive measures
Base your response on realistic cloud/infrastructure patterns and include actual command examples.Expected Output
Claude will simulate a complete incident response with triage, investigation commands, mitigation strategies, and communication plans.
Tips for Better Prompts
Always specify the programming language first—Claude's responses differ dramatically between Python, JavaScript, and Go. I learned this the hard way when Claude gave me Python-style async code for a Go project.
Upload your actual code files instead of pasting. Claude's 200K context window handles entire codebases. I regularly upload 5-10 files at once for architecture reviews—it sees connections you'll miss.
Chain prompts for complex tasks: Start with 'Design System Architecture,' then use the output as input for 'Write Comprehensive Tests.' This mimics how senior developers work—design first, implement second.