copilot-developer copilot-instructions.md

A set of writing rules for creating GitHub Copilot prompts, instructions, and chat modes. GitHub Copilot is a coding assistant, and these resources control how it is guided.

In plain words
What is it for?
Use it when authoring or reviewing Copilot resource files such as .prompt.md, .instructions.md, and .chatmode.md files.
Why use it?
It removes uncertainty about file names, required front matter, descriptions, and writing conventions.

Instructions file for GitHub Copilot

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add instructions/abilenduke/copilot-developer/copilot-instructions
Clone the repo
git clone --depth 1 https://github.com/ABilenduke/copilot-developer

Made for: GitHub Copilot.

Per session 1,009 This file is loaded in full into every session.
When invoked 1,009 The same file — it is already loaded in full.
Security scan A 0 findings. Scan, not verified.
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 $0.01009 $0.01009
Opus 5 $0.00504 $0.00504
Sonnet 5 $0.00202 $0.00202
Haiku 4.5 $0.00101 $0.00101

Measured yesterday against content hash cd551827b778, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

copilot-developer 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 yesterday.

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 · 100 lines

How it starts

The opening of the file, as written. The whole thing — 100 lines — stays where its author put it; the contents beside it link to each section on GitHub.

GitHub Copilot Instructions for Authoring Copilot Resources

The following instructions define the standards for creating new resource files (prompts, instructions, chat modes) for the copilot-developer repository. When I ask you to help me create, write, or review one of these files, your primary goal is to ensure the final Markdown file is well-structured, follows all repository conventions, and is easy for others to understand.


1. General Principles for All Files

These rules apply to all .md files you help me create.

  • File Naming: When creating a new file, suggest a kebab-case filename (e.g., my-new-prompt.prompt.md).
  • Front Matter is Mandatory: Every file must start with a valid Markdown front matter block enclosed by ---.
  • Description Field: The front matter must contain a description field.
    • The description should be a concise, single sentence explaining the resource's purpose.
    • The description's value must be wrapped in single quotes.
  • Clarity is Key: The content of the file (the prompt text, instructions, etc.) should be clear, unambiguous, and well-commented where necessary.

2. Creating New Prompt Files (.prompt.md)

When I ask you to "create a new prompt for X".

  • Scaffold Structure: Generate the file with the following front matter structure, prompting me for details:

    ---
    description: "A brief, clear description of what the prompt does."
    mode: agent # or ask
    model: # (Optional) e.g., gpt-5-mini
    tools: # (Optional) e.g., [terminal]
    ---
    (The prompt text itself goes here)
    
  • Mode Field: The mode field is required and must be either agent or ask. Default to agent if I don't specify.

  • Encourage model and tools: Proactively ask if the prompt is optimized for a specific model (like gpt-5-mini) or requires certain tools (like terminal). These are not required but are highly encouraged for quality.

  • Prompt Content:

    • The prompt text should be specific and give the AI a clear role, context, and task.
    • Use Markdown formatting (like headings and lists) to structure complex prompts.

Read the full file on GitHub · 100 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. yesterday First seen · 100 lines · 1,009 tokens per session scan A cd551827b778

Subscribe to this mod's changes

copilot-developer copilot-instructions.md is an instructions file published in the GitHub repository ABilenduke/copilot-developer (4 stars, last pushed 6mo ago), licensed MIT. It adds 1,009 tokens to every session, about $0.0050 per session on Opus 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 2026-08-31.

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