Borrowing it
Nothing to install: this file belongs to trilwu/secskills. 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/trilwu/secskills/main/.claude/skills/authoring-security-skills/SKILL.mdgit clone --depth 1 https://github.com/trilwu/secskillsWrote 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/trilwu/secskills/authoring-security-skills)<a href="https://agentmods.dev/skills/trilwu/secskills/authoring-security-skills"><img src="https://agentmods.dev/badge/skills/trilwu/secskills/authoring-security-skills/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/trilwu/secskills/authoring-security-skills"><img src="https://agentmods.dev/badge/skills/trilwu/secskills/authoring-security-skills.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector warn
SkillSpector: 1 finding, up to high
These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →
- high YARA Match · line 9 YARA rule matched a hack tool or exploit indicator (offensive tools, reconnaissance, privilege escalation, or exploit frameworks).Fix: Remove offensive tool references and exploit code. Legitimate agent skills should not contain penetration testing tools, exploit frameworks, or reconnaissance utilities.
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 | $0.00107 | $0.02916 |
| Opus 5 | $0.00053 | $0.01458 |
| Sonnet 5 | $0.00021 | $0.00583 |
| Haiku 4.5 | $0.00011 | $0.00292 |
Grade A, and why
authoring-security-skills 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 11d 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.
How it starts
The opening of the file, as written. The whole thing — 267 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Authoring Security Skills
A skill earns its context budget by carrying what the model would otherwise get
wrong. The model already knows what nmap -sV does. It does not reliably hold
the discipline — trace to demonstrated impact before reporting, preserve
before remediating, refuse to ship a rule never tested against production noise.
That judgment is the deliverable. Commands are scaffolding around it.
When to Use
- Adding a new skill to
secskills-offense,-defense, or-core - Splitting an overloaded skill or merging two that overlap
- Fixing a skill that loads for the wrong requests, or fails to load for the right ones
- Resolving a failure from
validate.py,sync_attack.py, orrun_evals.py
When NOT to Use
- Fact-checking content you have written — that is
verifying-skill-accuracy, and it is a separate gate that runs after this one - Editing prose in an existing, settled skill
- Repo-level work (manifests, marketplace, CI) that is not about a skill
Step 1: Pick the Plugin
A skill lives in exactly one plugin. The split exists so a blue-team user is not carrying exploitation content and vice versa.
| Plugin | Takes | Test |
|---|---|---|
secskills-offense |
Exploitation, attacker tradecraft, and testing that acts against a target | Would this run against someone's system during an engagement? |
secskills-defense |
DFIR, hunting, detection, intel, incident response | Does this read artifacts after the fact, or build detection? |
secskills-core |
Dual-use: reverse engineering, code/crypto/supply-chain review, AI security, ATT&CK mapping, reporting | Is it equally at home on both sides? |
When it fits two, choose core rather than duplicating. Cross-plugin
references are expected and degrade to inert text for readers who installed
only one plugin — that is by design, so never duplicate a skill to avoid a
cross-reference.
Step 2: Pick the Tier
Domain skills carry methodology for a whole area and trigger on broad, plain-language requests. Keep them few and non-overlapping.
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.
- 11d ago First seen · 267 lines · 107 tokens per session scan A 2bce9e85ffe3
authoring-security-skills is a skill published in the GitHub repository trilwu/secskills (138 stars, last pushed 6d ago), licensed MIT. It adds 107 tokens to every session and 2,916 once invoked, about $0.0005 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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