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 antropos17/Aegis --skill aegis-tddgit clone --depth 1 https://github.com/antropos17/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/antropos17/aegis/aegis-tdd)<a href="https://agentmods.dev/skills/antropos17/aegis/aegis-tdd"><img src="https://agentmods.dev/badge/skills/antropos17/aegis/aegis-tdd/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/skills/antropos17/aegis/aegis-tdd"><img src="https://agentmods.dev/badge/skills/antropos17/aegis/aegis-tdd.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 | $0.00046 | $0.00887 |
| Opus 5.5 | $0.00018 | $0.00355 |
| Sonnet 5.5 | $0.00009 | $0.00177 |
| Haiku 4.5 | $0.00005 | $0.00089 |
Grade A, and why
aegis-tdd 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 today.
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.
How it starts
The opening of the file, as written. The whole thing — 48 lines — stays where its author put it; the contents beside it link to each section on GitHub.
AEGIS test-driven changes
Adapted from Matt Pocock's tdd skill; attribution and terms: LICENSE.
Choose a contract already grounded in the project
Read the active checkout's AGENTS.md, current source and nearby tests. Use aegis-context for navigation and testing for test harness conventions when available. If a worktree lacks these ignored local skills, read the checkout's package.json, Vite and Vitest configurations directly. Never choose a renderer directory from an old handoff alone.
Translate the user's request or existing documented invariant into an observable expectation. Choose the public boundary already used by the code, state it briefly, and proceed. No repeated approval is needed for an ordinary authorized test/fix. Ask only when unresolved expected behavior materially changes the implementation. Preserve concurrent work and do not delegate unless the user requests it.
Put the test where the bug occurs
For main-process CommonJS code, native require needs the existing dependency seams/cache pattern; vi.mock alone is insufficient. Reuse init(deps), _setDepsForTest() and _resetForTest() where supported, and restore timers, mocks and shared state. For renderer tests, use the active Vitest project and its configured jsdom/Svelte environment. Match file extensions to the actual test include patterns.
The test boundary must reach the production caller and observe its output. Examples to select only when the change concerns them:
- Same PID reused by another process, or simultaneous same-named agents: observations remain attached to the correct instance.
- Observation outage followed by recovery: existing sessions are not falsely ended or split.
- Unknown ownership: no unrelated agent receives the event as a fallback.
- Audit overflow or unwritable storage: persisted-chain validity and loss visibility remain separate facts.
- IPC or renderer updates: the active consumer receives and displays the intended state; malformed or missing input follows its documented contract.
What ships with it
2 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.
- today First seen · 48 lines · 46 tokens per session scan A 48970f680314
aegis-tdd is a skill published in the GitHub repository antropos17/Aegis (157 stars, last pushed today), licensed MIT. It adds 46 tokens to every session and 887 once invoked, about $0.0002 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 2026-10-17.
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