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.
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.
npx skills add GanyuanRan/Aegis --skill using-aegisgit 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/skills/ganyuanran/aegis/using-aegis)<a href="https://agentmods.dev/skills/ganyuanran/aegis/using-aegis"><img src="https://agentmods.dev/badge/skills/ganyuanran/aegis/using-aegis.svg" alt="Measured on agentmods" height="20"></a>- NVIDIA SkillSpector pass
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 | $0.00018 | $0.00651 |
| Opus 5 | $0.00009 | $0.00326 |
| Sonnet 5 | $0.00004 | $0.00130 |
| Haiku 4.5 | $0.00002 | $0.00065 |
Grade A, and why
using-aegis 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 8d 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
Skip for subagents.
Hot Path
- User/project instructions outrank Aegis.
- Load only the smallest explicitly requested or clearly relevant skill/reference; otherwise stay on the fast path.
- Active codebase question/"what next": check README/ADR/rules/baseline, else
bounded index-first scan. Non-trivial work passively use relevant
CONTEXT-MAP.md/CONTEXT.md; model semantic conflicts only when found. - Primary routes:
grill me/grill this plan/审问我/盘问我/拷问我->brainstorming(literal/explanatory uses do not);/aegis-goalorAegis goal:->goal-framing. Bug, failure, regression, or unexpected behavior routes tosystematic-debugging. - Implementation only: Classify before implementation. Low stays owner-local; Medium/high: baseline read-set + plan. Spec Brief or Design Spec only for ambiguous/contract/cross-module medium/high work. TDD: off=no auto route/load; auto=risk-based strict/light/skipped; explicit strict applies. Pure explanation and read-only diagnosis skip implementation/TDD/write gates.
- For writes, the owner workflow surfaces Change Necessity, records
TaskStartSnapshot, and decidesArchitectureReviewRequired; ceremony alone never creates a branch/worktree. - At the first substantive user-visible stage say why Aegis is shaping
non-tiny work; do not wait for the user to ask. structured trace is only for audit/debug/release/long-task review/asked and does not route (
Trace Digest). - Workspace support is lazy; use configured Aegis workspace support only when records are needed. Q&A/status writes no project files; tiny work writes no workspace docs unless its owner requires a durable record.
- Tool/log/memory/search outputs are evidence candidates, not prompt payloads: summary first; large input index->window->excerpt. Bound history/session/ transcript/log reads by scope/time/lines.
- Read
references/skill-discipline.mdonly when route/order/TDD/workspace/ context re-entry/host mapping detail is needed.
Contract: only a real fast path emits Route: fast-path and an Aegis Reason Note; a routed skill owns its next-stage contract.
What ships with it
5 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 8d ago First seen · 46 lines · 18 tokens per session scan A 5728574e8f20
using-aegis is a skill published in the GitHub repository GanyuanRan/Aegis (1,172 stars, last pushed yesterday), licensed MIT. It adds 18 tokens to every session and 651 once invoked, about $0.0001 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 2026-08-30.
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