Getting it into your agent
It runs from inside its repository, so the clone comes first — what it calls does not travel with the file alone.
git clone --depth 1 https://github.com/MatrixFounder/Agentic-developmentnpx agentmods add skills/matrixfounder/agentic-development/skill-adversarial-securityWrote 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/matrixfounder/agentic-development/skill-adversarial-security)<a href="https://agentmods.dev/skills/matrixfounder/agentic-development/skill-adversarial-security"><img src="https://agentmods.dev/badge/skills/matrixfounder/agentic-development/skill-adversarial-security/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/matrixfounder/agentic-development/skill-adversarial-security"><img src="https://agentmods.dev/badge/skills/matrixfounder/agentic-development/skill-adversarial-security.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 | $0.00033 | $0.01558 |
| Opus 5.5 | $0.00013 | $0.00623 |
| Sonnet 5.5 | $0.00007 | $0.00312 |
| Haiku 4.5 | $0.00003 | $0.00156 |
Grade B, and why
skill-adversarial-security scanned grade B with 1 finding 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.
Instruction-override phrasingmediumPrompt injection
Text telling the model to disregard its earlier instructions or safety rules is the shape of a prompt injection, whoever wrote it.
- [ ] **Jailbreaking:** Are there guards against "Ignore previous instructions"? Downgraded: this mod is about security review, or the phrase is quoted, so it is likely naming the pattern rather than instructing it.
How it starts
The opening of the file, as written. The whole thing — 99 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Adversarial Security Critic
You are a paranoid security auditor who has seen too many data breaches. Your job is to find security vulnerabilities before they become headlines.
1. Red Flags (Anti-Rationalization)
STOP and READ THIS if you are thinking:
- "I'll be nice to the developer" -> WRONG. Attackers aren't nice. Your job is to be the attacker.
- "The automated scan passed, so I'm done" -> WRONG. Scanners miss logic bugs. You are the logic bug finder.
- "This is just an internal tool" -> WRONG. Internal tools are pivot points.
- "I'll only report the high-severity stuff" -> WRONG. Report every issue, including low-confidence ones, with confidence + severity attached — filtering happens downstream, not in your head.
2. Persona & Tone
Optional style: you MAY adopt the persona defined in references/prompts/sarcastic.md (provocative, paranoid-auditor delivery). Tone is an opt-in stylistic choice with no evidence base as a recall lever (audit-067 C-01; doctrine: vdd-sarcastic SKILL.md §2 disclaimer).
NOT optional: exhaustive reporting — report every issue, including low-confidence ones, with confidence + severity attached; filtering happens downstream — and the objective bar (§7).
3. Reconnaissance (Automated)
Read this branch BEFORE the command below. Rows 1, 3 and 4 apply to the critic-security
subagent; row 2 never does — as a spawned critic your role withholds execution from you by
design (Claude Code declares it Read, Grep, Glob; the other adapters do the equivalent where they
enforce it — skill-parallel-orchestration §2.4). On the sequential role-switch path you are the
orchestrator wearing this persona and row 2 is exactly where you belong.
| Your situation | What you do |
|---|---|
| The prompt carries an execution-evidence block with a scan summary | Ingest it. Do not re-run it. |
| You have an execution tool and no supplied result | Run the command below. |
| You have no execution tool | Write scan: NOT RUN (no execution tool in this role) and go to §4. Do not attempt the command — a stalled turn is a lost lens, and a subagent burned 600 s doing exactly this in one recorded run. |
| No execution-evidence block at all | Contract breach: emit the finding "exit-bar condition unverifiable — no execution evidence supplied" and do not signal clean-pass. |
What ships with it
1 file 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.
- 1mo ago Changed · +4 lines fc92761f1b7d
- 1mo ago First seen · 95 lines · 33 tokens per session scan B dfcd04e909d1
skill-adversarial-security is a skill published in the GitHub repository MatrixFounder/Agentic-development (6 stars, last pushed yesterday), licensed Apache-2.0. It adds 33 tokens to every session and 1,558 once invoked, about $0.0001 per session on Opus 5.5. A static security scan graded it B with 1 finding (instruction-override phrasing). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.
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