Prompt repository Engineering & code

Prompt templates for coding agents

11 briefs for Claude Code, Codex, Cursor and other coding agents, plus prompts for design docs and pull request write-ups. Every agent brief ends with a check the agent can run, such as a failing test that must pass, so you know when the job is really done.

Prompts: 11
Registry code: ENG
Average score: 10 out of 10
Works in: ChatGPT, Claude, Gemini and Copilot

The 11 prompts

ENG-001Brief a coding agent to fix a bugYou are handing a bug to Claude Code, Codex or another coding agent and want a root-cause fix with proof, not a guess.Code agent10 out of 10
ENG-002Brief a coding agent to add tests before a refactorA module has thin or no test coverage, and you want an agent to pin down its behavior without changing it.Code agent10 out of 10
ENG-003Explain unfamiliar code before you change itYou have inherited code you did not write and need to understand what it really does before touching it.Claude10 out of 10
ENG-004Write a pull request description from a diffYou have finished a change and want a description reviewers can use, with the why, the risks and how to test it.GPT10 out of 10
ENG-005Review a code change against a checklistYou want a second pair of eyes on a diff before a human review, with findings ranked by how much they matter and nothing invented.Claude10 out of 10
ENG-006Explain an error or log and find the likely causeSomething failed with an error message, stack trace or log you do not fully understand, and you want the likely causes ranked with a way to confirm each.GPT10 out of 10
ENG-007Write unit tests for one functionYou have a single function and want focused tests that cover the normal cases, the edges and the errors, in your project's test framework.Gemini10 out of 10
ENG-008Write API reference docs from the codeAn internal or public API has endpoints nobody documented, and you want reference docs written from what the code actually does.Any chat10 out of 10
ENG-009Brief a coding agent to build a small featureYou are handing a well-defined feature to Claude Code, Codex or another coding agent and want a plan first, code that fits the codebase, and tests as proof.Code agent10 out of 10
ENG-010Brief a coding agent to refactor without changing behaviorYou need a coding agent to clean up code while tests keep passing and behavior stays the same.Claude10 out of 10
ENG-011Write a short technical design documentYou need the problem, approach, alternatives and risks written up before the team builds.Any chat10 out of 10

How to use them

Open a prompt and press Fill in variables. Type your details into each blank; they stay in your browser.
Copy the filled prompt into ChatGPT, Claude, Gemini or Copilot, or check it first in the Prompt Grader.
Read the answer against your own facts before you use it. The Fact Check List shows what to check.

Questions

How do I write a good prompt for a coding agent?

Say what done looks like in a way the agent can check: a test that must pass, a command that must succeed, files it must not touch. The briefs here are laid out that way, which stops an agent from declaring victory early.

Do these prompts work in Claude, Gemini and Copilot?

Yes. Each prompt is laid out for one kind of model, shown beside it, but every one works in ChatGPT, Claude, Gemini and Microsoft Copilot. Fill in the blanks and paste the whole prompt into the chat.

Are these prompts free?

Yes. You can open ten prompts without signing up, and a free email unlocks all 319 in the repository. Use them in your own work and your clients' work; please do not republish the collection.