Aegis is a method pack that guides coding agents to inspect a project's baseline, make bounded changes, and verify their work with fresh evidence. It is for people using coding-agent hosts who want fewer unverified changes and less unnecessary process. The catalogue add-ons implement this method through skills, instructions, commands, a hook, and a plugin.
Borrowing it
Nothing to install: this file belongs to GanyuanRan/Aegis. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/GanyuanRan/Aegis/main/.github/copilot-instructions.mdgit clone --depth 1 https://github.com/GanyuanRan/AegisWrote 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.
[](https://agentmods.dev/instructions/ganyuanran/aegis/copilot-instructions)<a href="https://agentmods.dev/instructions/ganyuanran/aegis/copilot-instructions"><img src="https://agentmods.dev/badge/instructions/ganyuanran/aegis/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.
<a href="https://agentmods.dev/instructions/ganyuanran/aegis/copilot-instructions"><img src="https://agentmods.dev/badge/instructions/ganyuanran/aegis/copilot-instructions.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00149 | $0.00149 |
| Opus 5.5 | $0.00060 | $0.00060 |
| Sonnet 5.5 | $0.00030 | $0.00030 |
| Haiku 4.5 | $0.00015 | $0.00015 |
Grade A, and why
Aegis 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 1mo 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.
What it actually says
Aegis for GitHub Copilot
This repository uses Aegis as method-pack workflow discipline.
Before risky implementation, prefer the smallest relevant Aegis skill from
.github/skills/ or the linked Aegis skill directories. Keep detailed workflow
logic in the skill body rather than duplicating it here.
Key repository boundaries:
- treat Aegis as
Aegis Method Pack (runtime-ready), not a runtime core - keep user instructions and target-project rules above Aegis guidance
- do not claim authoritative
GateDecisionor final completion authority - require fresh verification evidence before completion claims
- keep repository instructions concise; do not replace skill bodies with a long fixed prompt
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.
- 1mo ago First seen · 17 lines · 149 tokens per session scan A 2b2798c02829
Aegis copilot-instructions.md is an instructions file published in the GitHub repository GanyuanRan/Aegis (1,383 stars, last pushed 4d ago), licensed MIT. It adds 149 tokens to every session, about $0.0006 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.
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