Coding & Technical Prompts

Templates for debugging, explaining, writing, and reviewing code. These work whether you’re a seasoned developer or just getting started with scripting.

Debug This Error

When to use it: You hit an error message and don’t know what’s causing it or how to fix it.

I'm getting the following error. Help me debug it.

Error message:
[PASTE THE FULL ERROR MESSAGE HERE]

Relevant code:
[PASTE THE CODE SECTION WHERE THE ERROR OCCURS]

Context:
- Language/framework: [e.g., Python 3.11, Node.js, React]
- What I was trying to do: [ONE SENTENCE DESCRIPTION]
- What I've already tried: [ANY FIXES YOU ATTEMPTED]

!!! tip Always include the full error message, not just the last line. Stack traces have the context Claude needs to diagnose the root cause quickly.

Explain This Code

When to use it: You’re reading someone else’s code (or your own from 6 months ago) and need to understand what it does.

Explain the following code to me. I [am new to programming / have intermediate experience / am experienced but unfamiliar with this library].

Walk through what it does step by step. For any patterns or concepts that aren't obvious, explain them briefly.

Code:
[PASTE YOUR CODE HERE]

!!! example “Filled-in example” Explain the following code to me. I am new to programming.

Walk through what it does step by step. For any patterns or concepts that aren't obvious, explain them briefly.

Code:
def process_items(items):
    return [item.strip().lower() for item in items if item]

!!! tip Add “Focus especially on [X]” to direct attention to the part you’re most confused about. Useful for large files.

Write a Script to Do X

When to use it: You need a one-off script to automate something and don’t want to write it from scratch.

Write a [Python/Bash/JavaScript] script that does the following:

Task: [DESCRIBE WHAT THE SCRIPT SHOULD DO]

Inputs: [WHAT DATA OR FILES IT RECEIVES]
Outputs: [WHAT IT SHOULD PRODUCE]
Requirements:
- [REQUIREMENT 1]
- [REQUIREMENT 2]

Keep it simple and well-commented. If there are multiple approaches, use the most straightforward one.

!!! example “Filled-in example” Write a Python script that does the following:

Task: Read a CSV file of email addresses, remove duplicates, and output a cleaned CSV.

Inputs: A CSV file with a column called "email"
Outputs: A new CSV file called "emails_clean.csv"
Requirements:
- Case-insensitive deduplication ([email protected] and [email protected] are the same)
- Print a summary of how many duplicates were removed

Keep it simple and well-commented.

!!! tip If you need it to run in a specific environment, mention it: “This will run on a Mac” or “This runs inside a Docker container with Python 3.11.”

Convert Code to Another Language

When to use it: You have working code in one language and need it in another.

Convert the following [SOURCE LANGUAGE] code to [TARGET LANGUAGE].

Preserve the same logic and behavior. Use idiomatic patterns for the target language — don't just do a line-by-line translation. Add a brief note if anything doesn't translate directly.

Code:
[PASTE YOUR CODE HERE]

!!! tip Specify the version if it matters: “Python 3.12” or “ES2020 JavaScript.” Some language features don’t exist in older versions.

Write Tests for This Function

When to use it: You have a function and want test coverage but don’t want to write all the test cases manually.

Write unit tests for the following function.

Testing framework: [pytest / Jest / JUnit / etc., or "whatever is standard for this language"]

Cover:
- The happy path (normal expected inputs)
- Edge cases (empty inputs, boundary values, unexpected types)
- Error cases (inputs that should raise exceptions or return errors)

Function:
[PASTE YOUR FUNCTION HERE]

!!! tip After getting the tests, ask “what cases did you not cover and why?” — Claude will often flag scenarios it deliberately skipped.

Review This Code for Bugs and Improvements

When to use it: You want a code review before merging, shipping, or sharing something.

Review the following code and give me two separate sections:

1. Bugs and issues: anything that will cause errors, unexpected behavior, or security problems
2. Improvement suggestions: readability, performance, better patterns — things that aren't bugs but make the code better

Be specific. For each item, explain what the problem is and how to fix it.

Language/framework: [LANGUAGE OR FRAMEWORK]

Code:
[PASTE YOUR CODE HERE]

!!! tip Add “Focus especially on security” or “Focus especially on performance” if you have a specific concern.

Create a README for This Project

When to use it: You’ve built something and need documentation so other people (or future you) can understand and use it.

Write a README.md for the following project.

Include:
- What it does (1-2 sentences)
- Requirements / dependencies
- How to install and set it up
- How to use it (with a basic example)
- Any important configuration or environment variables

Project description:
[DESCRIBE YOUR PROJECT OR PASTE RELEVANT CODE]

Tech stack: [LANGUAGE, FRAMEWORKS, KEY LIBRARIES]

!!! tip Paste your main file or entry point along with the description — Claude can infer a lot about requirements and usage from the actual code.

Explain a Technical Concept Simply

When to use it: You need to understand something new, or explain it to someone without a technical background.

Explain [TECHNICAL CONCEPT] in plain terms.

My background: [no programming experience / some programming / experienced developer unfamiliar with this area]
Use an analogy if it helps. Give a brief real-world example of when this matters.
Keep it under 200 words unless more depth is genuinely needed.

!!! example “Filled-in example” Explain “idempotency” in plain terms.

My background: experienced developer unfamiliar with this area.
Use an analogy if it helps. Give a brief real-world example of when this matters.
Keep it under 200 words unless more depth is genuinely needed.

Generate Sample Data for Testing

When to use it: You need realistic test data to develop against and don’t want to invent it yourself.

Generate [NUMBER] rows of sample data in [FORMAT: JSON / CSV / SQL INSERT statements] for the following schema:

[DESCRIBE THE DATA STRUCTURE OR PASTE YOUR SCHEMA]

Requirements:
- Make the data realistic (real-looking names, plausible numbers, valid formats)
- Include variety — don't repeat the same values
- [ANY SPECIFIC CONSTRAINTS, e.g., "dates should be within the last 90 days"]

!!! tip For sensitive fields like emails or phone numbers, ask Claude to generate realistic-looking but clearly fake data: “use @example.com domains” or “use 555-xxxx phone numbers.”

Find the Simplest Way to Do X

When to use it: You know what you want to accomplish but aren’t sure of the best approach, or your current solution feels overcomplicated.

What is the simplest way to [DESCRIBE WHAT YOU WANT TO DO] in [LANGUAGE/FRAMEWORK]?

Context: [BRIEF DESCRIPTION OF YOUR SITUATION]

I want the most straightforward approach — not the most elegant or scalable one. If there's a built-in way to do this, show me that first. Include a working code example.

!!! tip “Simplest” is a more useful constraint than “best.” It pushes Claude toward practical, readable solutions rather than impressive but complex ones.