agentmods.dev

dev-challenge: Instructions file for GitHub Copilot

.github/copilot-instructions.md

dev-challenge copilot-instructions.md is an instructions file for GitHub Copilot from micheltlutz/dev-challenge. It costs 690 tokens per session, scanned A, original, MIT.

Instructions for a GitHub Copilot coding challenge project, including how to mentor learners and where the official challenge specifications live. GitHub Copilot is an AI assistant that helps write and explain code.

In plain words
What is it for?
Reading challenge requirements, reviewing learner code, explaining failed acceptance criteria, and updating the specification and tests when API behaviour changes.
Why use it?
They keep answers aligned with the tested specification and encourage teaching rather than silently completing learning exercises.

Instructions file for GitHub Copilot

Written for GitHub Copilot: a Copilot instructions file. Also seen: mentions AGENTS.md.

This is micheltlutz/dev-challenge's own configuration. It tells GitHub Copilot how to work on dev-challenge itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything dev-challenge configures →

Needs its repository: it runs a file that does not travel with it, so clone the repository first. The line is python scripts/export_openapi.py --check.

not rated 33repo 5d ago A scan 690 tokens original MIT
View source ↗ micheltlutz/dev-challenge micheltlutz.me
Reuse

Borrowing it

Nothing to install: this file belongs to micheltlutz/dev-challenge. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/micheltlutz/dev-challenge/main/.github/copilot-instructions.md
Clone the repo
git clone --depth 1 https://github.com/micheltlutz/dev-challenge

Made for: GitHub Copilot.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for dev-challenge copilot-instructions.md

README.md
[![agentmods](https://agentmods.dev/badge/instructions/micheltlutz/dev-challenge/copilot-instructions/github.svg)](https://agentmods.dev/instructions/micheltlutz/dev-challenge/copilot-instructions)
Your own site
<a href="https://agentmods.dev/instructions/micheltlutz/dev-challenge/copilot-instructions"><img src="https://agentmods.dev/badge/instructions/micheltlutz/dev-challenge/copilot-instructions/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for dev-challenge copilot-instructions.md

Your own site · 80×15
<a href="https://agentmods.dev/instructions/micheltlutz/dev-challenge/copilot-instructions"><img src="https://agentmods.dev/badge/instructions/micheltlutz/dev-challenge/copilot-instructions.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 690 This file is loaded in full into every session.
When invoked 690 The same file — it is already loaded in full.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00690 $0.00690
Opus 5.5 $0.00276 $0.00276
Sonnet 5.5 $0.00138 $0.00138
Haiku 4.5 $0.00069 $0.00069

Measured 2mo ago against content hash a6a24ffa3187, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

dev-challenge copilot-instructions.md scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2mo ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.github/copilot-instructions.md · 71 lines

How it starts

The opening of the file, as written. The whole thing — 71 lines — stays where its author put it; the contents beside it link to each section on GitHub.

GitHub Copilot instructions

Mirror of AGENTS.md. Read that file for the full picture; this is the short version Copilot loads automatically.

Which job are you doing?

Helping someone do a challenge — they are learning. Default to mentoring: plan with them, review their code, explain which acceptance criterion fails and why. Do not write the implementation unless they ask. If they ask, do it properly and without fuss. Scaffolding, config and boilerplate are always fine to write outright.

Improving the lab itself — normal engineering work. See CONTRIBUTING.md.

The spec layer is the source of truth

specs/ — not the code, not readme_files/ (those are redirect stubs).

Before answering what a challenge requires, read specs/challenges/<id>/spec.md and its acceptance.md. The old briefs disagreed with the running API for a long time; this layer exists so that cannot recur, and CI enforces it.

If you change API behaviour, update the spec and the harness test in the same commit.

Layout

  • app/ — reference FastAPI API
  • specs/ — challenges, acceptance criteria, OpenAPI contract, design tokens
  • harness/ — black-box verifier, reports per acceptance criterion
  • scripts/ — seed.py, export_openapi.py, build_tokens.py, validate_specs.py

Commands

ruff check app scripts tests harness
pytest --cov=app
python scripts/export_openapi.py --check
python scripts/build_tokens.py --check
python scripts/validate_specs.py
python harness/cli.py --base-url http://localhost:3000 --challenge backend-05-balance

Fixture

[email protected] (5 statements, balance 15491.00) and [email protected] (1 statement, balance 4200.00). Password Challenge@123 for both. Plus 40 rows belonging to neither, which is what makes the scoping criteria bite.

Easy things to get wrong

  • Primary buttons are near-black #19191C, not purple. Purple is brand surfaces only. Import specs/design/tokens.css; do not hard-code hex.
  • Credit #0CB97B, debit #E02244, and colour is never the only signal — keep the sign and the arrow.
  • Web and mobile specs declare testids. The harness drives the UI through them; omitting them makes the work unverifiable.
  • Balances and statement lists are per user. A statement is yours when your full name is from_user or to_user. Returning the global ledger is the commonest back-end mistake.
  • Mobile tokens go in Keychain/Keystore, never AsyncStorage or UserDefaults.
  • Never commit a secret. app/.env is git-ignored; use app/.env.example.

Read the full file on GitHub · 71 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 2mo ago First seen · 71 lines · 690 tokens per session scan A a6a24ffa3187

Subscribe to this mod's changes

dev-challenge copilot-instructions.md is an instructions file published in the GitHub repository micheltlutz/dev-challenge (33 stars, last pushed 5d ago), licensed MIT. It adds 690 tokens to every session, about $0.0028 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

MobilePlanningchallengedevelopmentfastapifront-endfront-end-challenge
Related

dev-challenge copilot-instructions.md compared with instructions from other repositories

dev-challenge copilot-instructions.md next to 6 instructions from other repositories
ModTypeStarsLast pushLicenceScanTokensWorks with
dev-challenge copilot-instructions.mdmicheltlutz/dev-challengeInstructions file335d agoMITA690GitHub Copilot
vscode buildNext.instructions.mdmicrosoft/vscodeInstructions file195kyesterdayMITA9,719GitHub Copilot
next.js AGENTS.mdvercel/next.jsInstructions file143ktodayMITA7,461Codex, OpenCode
langchain AGENTS.mdlangchain-ai/langchainInstructions file149kyesterdayMITA4,680Codex, OpenCode
vscode oss-third-party-notices.instructions.mdmicrosoft/vscodeInstructions file195kyesterdayMITA5,516GitHub Copilot
vscode copilot-instructions.mdmicrosoft/vscodeInstructions file195kyesterdayMITA3,093GitHub Copilot
deepseek-harness AGENTS.mddeepseek-ai/deepseek-harnessInstructions file274k2d agoMITA4,313Codex, OpenCode