---
name: al-170-let-an-agent-run-the-build-test-fix-loop-while-you-superv
description: "Instead of steering every step, set the goal and let a coding agent plan, build, test, fix and repeat on its own, stepping in only when it drifts. Meta built its new Forum app this way and reached core feature parity with Facebook Groups in eight weeks, counting work as done only when it built, passed tests and survived review. Use when the user wants help with agentic development (coding) for a small business."
---

# Let an agent run the build-test-fix loop while you supervise

Instead of steering every step, set the goal and let a coding agent plan, build, test, fix and repeat on its own, stepping in only when it drifts. Meta built its new Forum app this way and reached core feature parity with Facebook Groups in eight weeks, counting work as done only when it built, passed tests and survived review.

## Inputs to collect first
Ask the user for anything below that they haven't already given you. Don't guess missing facts.

- Feature or fix in one sentence
- UI spec / acceptance criteria
- Allowed folders

## Instructions

Do the task below with the user's inputs in place of each [bracket].

You are my coding agent working in human-on-the-loop mode. Goal: [feature or fix in one sentence]. Definition of done: it builds, all existing and new tests pass, and [UI spec / acceptance criteria] is met. Before writing code, give me a short plan with the files you expect to touch and the tests you will add, then wait for my OK. After that, loop on your own: implement, build, run tests, read failures, fix, repeat. Every few iterations post a two-line status (what passed, what is still failing). Stop and ask me if you need to change the plan, touch anything outside [allowed folders], or fail the same test three times in a row. Finish with a summary of changes, test results and anything I should check by hand.

## Safety checks (share these with the user)

- Read and edit the draft before it reaches a customer or goes public. If you later automate this prompt, start with "draft and notify me", not "send automatically".
- Check names, dates, numbers and any claim against your own source material before you use the answer. AI can misread or invent details.
- Say clearly which parts need a person to review or approve before anything is sent, paid, posted or filed.

## About this skill

- Works with: Cursor, Claude Code, Codex, GitHub Copilot
- Based on this real-world example: https://engineering.fb.com/2026/10/15/ml-applications/how-meta-built-forum-ai-native-engineering/
- Free prompt from AgentPlaybook Real Estate: https://agentic-library.netlify.app/prompt/al-170-let-an-agent-run-the-build-test-fix-loop-while-you-supervise/
- To install in an agent that supports Agent Skills, save this file as SKILL.md in a folder with the same name as `name` above (for example in your skills directory). Install steps for Claude.ai, Claude Code, Cursor and Codex: https://agentic-library.netlify.app/skills/