Borrowing it
Nothing to install: this file belongs to theMobiusStrip/agentpay-guard. 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/theMobiusStrip/agentpay-guard/main/.claude/skills/adversarial-review/SKILL.mdgit clone --depth 1 https://github.com/theMobiusStrip/agentpay-guardWrote 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/themobiusstrip/agentpay-guard/adversarial-review)<a href="https://agentmods.dev/skills/themobiusstrip/agentpay-guard/adversarial-review"><img src="https://agentmods.dev/badge/skills/themobiusstrip/agentpay-guard/adversarial-review/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/themobiusstrip/agentpay-guard/adversarial-review"><img src="https://agentmods.dev/badge/skills/themobiusstrip/agentpay-guard/adversarial-review.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 | $0.00143 | $0.00989 |
| Opus 5.5 | $0.00057 | $0.00396 |
| Sonnet 5.5 | $0.00029 | $0.00198 |
| Haiku 4.5 | $0.00014 | $0.00099 |
Grade A, and why
adversarial-review 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.
How it starts
The opening of the file, as written. The whole thing — 76 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Adversarial review — custody spine
The writing context does not get to grade its own work: it shares its own blind spots, which is exactly how a real overspend or fail-open slips through. The reviewer MUST be a separate subagent with fresh context.
Scope = the custody spine: the files in AGENTS.md → Security (the atomic
store, evaluate.ts, guard.ts, policy/*.ts, and the
x402-idempotency-middleware). If the diff doesn't touch those, say so and stop —
a broad code review is a different tool (/code-review).
1. Scope the diff
Collect the diff for the custody-spine files from the merge-base with the default branch to HEAD (or the working-tree diff if uncommitted). If none of those files changed, report "no custody-spine changes" and stop.
2. Independent review (Agent tool — a subagent that did NOT write this code)
Spawn a reviewer subagent. Give it: SECURITY.md, the AGENTS.md → Security
invariant table, the diff, and the files it touches. Instruct it to attack like a
staff custody/security engineer, not to confirm. For each hunk, find a concrete
way this change either widens an item in SECURITY.md's "Honest limitations" or
breaks a Security-table invariant. Hunt specifically for:
- Cap overspend / double-count in any interleaving — window-slide (pending reservation stops holding cap before terminal), settled spend dropped or double-counted, aggregate/per-payee accounting wrong.
- Early release —
releaseExpiredfreeing a still-settleable reservation; skew applied in the wrong direction;safeReleaseAtnot covering the signedvalidBefore. - Fail-open — a guard hook path that returns
void/undefined(⇒ allow) on error instead of{ abort: true }; an envelope/intent/dedup check bypassable. - Lifecycle mis-correlation —
onFailurereleasing a signed authorization's hold; ignoredtransition()CAS returns; nonce/FIFO correlation crossing concurrent identical payments. - Replay — the middleware keying on the client-supplied payment-identifier instead of the payer-signed authorization; a crash permanently stranding a payment; a stale worker overwriting a fresh grant.
- Honest-scope overclaim — a doc/comment claiming a guarantee the code doesn't provide, or relabeling arm A as "documented", or dropping a DrainBench fairness disclosure.
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 · 76 lines · 143 tokens per session scan A 9bf65decc07d
adversarial-review is a skill published in the GitHub repository theMobiusStrip/agentpay-guard (2 stars, last pushed 3mo ago), licensed MIT. It adds 143 tokens to every session and 989 once invoked, 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 2026-08-31.
Other skills, from other repositories
find-bugs
Find bugs, security vulnerabilities, and code quality issues in local branch changes. Use when asked to review changes, find bugs, security review, or audit code on the current branch.
code-review
Paranoid architect review of code changes for bugs, security, missing tests, and undocumented assumptions. Works on local git diffs OR a GitHub pull request (e.g. owner/repo N). For PRs, can post findings as line-level review comments.
parallel-pr-review
Use when asked to "review the open PRs", review a batch or stack of pull requests, or run a recurring PR-review pass on a repo — especially with many PRs, stacked branches, conflicts, or security-sensitive changes. Covers grouping, fan-out to review subagents, verdict synthesis, and posting.
independent-review
Incorporate feedback from an independent code reviewer to improve your solution. The reviewer is a different agent that analyzed your work.
qa-review
QA review for code changes — test coverage analysis, edge case identification, test plan generation, regression detection, test health tracking over time.
review-readiness
PR readiness dashboard — tracks which reviews have been completed per branch and gates merge decisions. Shows code review, tests, security, QA, and linting status.