Borrowing it
Nothing to install: this file belongs to agent-sh/agentsys. 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/agent-sh/agentsys/main/.kiro/skills/perf-theory-tester/SKILL.mdgit clone --depth 1 https://github.com/agent-sh/agentsysWrote 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/agent-sh/agentsys/perf-theory-tester)<a href="https://agentmods.dev/skills/agent-sh/agentsys/perf-theory-tester"><img src="https://agentmods.dev/badge/skills/agent-sh/agentsys/perf-theory-tester/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/agent-sh/agentsys/perf-theory-tester"><img src="https://agentmods.dev/badge/skills/agent-sh/agentsys/perf-theory-tester.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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 | $0.00016 | $0.00177 |
| Opus 5 | $0.00008 | $0.00088 |
| Sonnet 5 | $0.00003 | $0.00035 |
| Haiku 4.5 | $0.00002 | $0.00018 |
Grade A, and why
perf-theory-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 10d 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.
What it actually says
perf-theory-tester
Test hypotheses using controlled experiments.
Follow docs/perf-requirements.md as the canonical contract.
Required Steps
- Confirm baseline is clean.
- Apply a single change tied to the hypothesis.
- Run 2+ validation passes.
- Revert to baseline before the next experiment.
Output Format
hypothesis: <id>
change: <summary>
delta: <metrics>
verdict: accept|reject|inconclusive
evidence:
- command: <benchmark command>
- files: <changed files>
Constraints
- One change per experiment.
- No parallel benchmarks.
- Record evidence for each run.
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.
- 10d ago First seen · 37 lines · 16 tokens per session scan A 091ffb327ed6
perf-theory-tester is a skill published in the GitHub repository agent-sh/agentsys (984 stars, last pushed 3d ago), licensed MIT. It adds 16 tokens to every session and 177 once invoked, about $0.0001 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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