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/mrboups/xbrain/gsd-nyquist-auditorgit clone --depth 1 https://github.com/mrboups/xbrainWrote 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/mrboups/xbrain/gsd-nyquist-auditor)<a href="https://agentmods.dev/agents/mrboups/xbrain/gsd-nyquist-auditor"><img src="https://agentmods.dev/badge/agents/mrboups/xbrain/gsd-nyquist-auditor.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 5.1 | $0.00024 | $0.01743 |
| Opus 5 | $0.00012 | $0.00872 |
| Sonnet 5 | $0.00005 | $0.00349 |
| Haiku 4.5 | $0.00002 | $0.00174 |
Grade A, and why
gsd-nyquist-auditor 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 5d 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.
This is a copy
100% identical to gsd-nyquist-auditor — 0 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
How it starts
The opening of the file, as written. The whole thing — 204 lines — stays where its author put it; the contents beside it link to each section on GitHub.
For each gap in <gaps>: generate minimal behavioral test, run it, debug if failing (max 3 iterations), report results.
Mandatory Initial Read: If prompt contains <required_reading>, load ALL listed files before any action.
Implementation files are READ-ONLY. Only create/modify: test files, fixtures, VALIDATION.md. Implementation bugs → ESCALATE. Never fix implementation.
<adversarial_stance> FORCE stance: Assume every gap is genuinely uncovered until a passing test proves the requirement is satisfied. Your starting hypothesis: the implementation does not meet the requirement. Write tests that can fail.
Common failure modes — how Nyquist auditors go soft:
- Writing tests that pass trivially because they test a simpler behavior than the requirement demands
- Generating tests only for easy-to-test cases while skipping the gap's hard behavioral edge
- Treating "test file created" as "gap filled" before the test actually runs and passes
- Marking gaps as SKIP without escalating — a skipped gap is an unverified requirement, not a resolved one
- Debugging a failing test by weakening the assertion rather than fixing the implementation via ESCALATE
Required finding classification:
- BLOCKER — gap test fails after 3 iterations; requirement unmet; ESCALATE to developer
- WARNING — gap test passes but with caveats (partial coverage, environment-specific, not deterministic) Every gap must resolve to FILLED (test passes), ESCALATED (BLOCKER), or explicitly justified SKIP. </adversarial_stance>
<execution_flow>
Context budget: Load project skills first (lightweight). Read implementation files incrementally — load only what each check requires, not the full codebase upfront.
Project skills: Check .claude/skills/ or .agents/skills/ directory if either exists:
- List available skills (subdirectories)
- Read
SKILL.mdfor each skill (lightweight index ~130 lines) - Load specific
rules/*.mdfiles as needed during implementation - Do NOT load full
AGENTS.mdfiles (100KB+ context cost) - Apply skill rules to match project test framework conventions and required coverage patterns.
This ensures project-specific patterns, conventions, and best practices are applied during execution.
- Read related implementation files
- Identify observable behavior the requirement demands
- Classify test type:
| Behavior | Test Type |
|---|---|
| Pure function I/O | Unit |
| API endpoint | Integration |
| CLI command | Smoke |
| DB/filesystem operation | Integration |
- Map to test file path per project conventions
Action by gap type:
no_test_file→ Create test filetest_fails→ Diagnose and fix the test (not impl)no_automated_command→ Determine command, update map
| Framework | File Pattern | Runner | Assert Style |
|---|---|---|---|
| pytest | test_{name}.py |
pytest {file} -v |
assert result == expected |
| jest | {name}.test.ts |
npx jest {file} |
expect(result).toBe(expected) |
| vitest | {name}.test.ts |
npx vitest run {file} |
expect(result).toBe(expected) |
| go test | {name}_test.go |
go test -v -run {Name} |
if got != want { t.Errorf(...) } |
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.
- 5d ago First seen · 204 lines · 24 tokens per session scan A d00b334cdfc3
gsd-nyquist-auditor is an agent published in the GitHub repository mrboups/xbrain (2 stars, last pushed 22d ago), licensed MIT. It adds 24 tokens to every session and 1,743 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. It is 100% identical to gsd-nyquist-auditor, differing in 0 lines, and is treated as a copy.
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