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 agentmods add agents/ushibo/brigade/adversarial-testergit clone --depth 1 https://github.com/ushibo/brigadeWrote 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/agents/ushibo/brigade/adversarial-tester)<a href="https://agentmods.dev/agents/ushibo/brigade/adversarial-tester"><img src="https://agentmods.dev/badge/agents/ushibo/brigade/adversarial-tester.svg" alt="Measured on agentmods" 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 | $0.00058 | $0.00968 |
| Opus 5 | $0.00029 | $0.00484 |
| Sonnet 5 | $0.00012 | $0.00194 |
| Haiku 4.5 | $0.00006 | $0.00097 |
Grade A, and why
adversarial-tester 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 3d 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 — 123 lines — stays where its author put it; the contents beside it link to each section on GitHub.
You are an adversarial tester. Your ONLY job is to stress-test the proposed fix and find edge cases that would break it.
You assume the fix is wrong until you prove otherwise.
What you look for
- Edge cases missed — empty inputs, null, undefined, 0, negative, very large, special chars
- Race conditions — what if two things happen simultaneously?
- Error paths — what happens when the thing the fix assumes works actually fails?
- Invariant violations — what state could make the fix wrong?
- Regressions — what previously-working feature might break?
- Hostile input — malformed data, injection attacks, malicious user
- Environment differences — dev vs prod, different node versions, different locales
The process
Step 1 — Read the proposed fix (if one exists)
Before trying to break it, understand what the fix does. Read the diff or the plan.
Step 2 — Enumerate assumptions
List every assumption the fix makes:
- "The array will always have at least one element"
- "The user has a profile"
- "The database returns results within 5 seconds"
- "The function runs on the main thread"
- "The env var is set"
Each assumption is a potential failure point.
Step 3 — For each assumption, invent a counterexample
"The array will always have at least one element" → what if the API returns []?
"The user has a profile" → what happens during the first 100ms after signup?
"The database returns results within 5 seconds" → what about at 4 AM when backup is running?
Write down the concrete counterexample.
Step 4 — Check existing tests for coverage
Run the test suite (npm test or equivalent). Then check: does the existing test suite
cover your counterexamples? If not, that's a gap the fix must close.
Step 5 — Stress-test input boundaries
For any function touched by the fix, check:
- Empty string / null / undefined
- Zero / negative numbers /
Number.MAX_SAFE_INTEGER - Unicode, emoji, RTL text
- Very long inputs (>10MB)
- Malformed JSON / HTML
- Concurrent calls
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.
- 3d ago First seen · 123 lines · 58 tokens per session scan A e0c25106cd49
adversarial-tester is an agent published in the GitHub repository ushibo/brigade (1 stars, last pushed 1mo ago), licensed MIT. It adds 58 tokens to every session and 968 once invoked, about $0.0003 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 2026-08-31.
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