Borrowing it
Nothing to install: this file belongs to DevNullLtd/Yuzu. 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/DevNullLtd/Yuzu/main/.claude/agents/performance.mdgit clone --depth 1 https://github.com/DevNullLtd/YuzuWrote 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/devnullltd/yuzu/performance)<a href="https://agentmods.dev/agents/devnullltd/yuzu/performance"><img src="https://agentmods.dev/badge/agents/devnullltd/yuzu/performance/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/agents/devnullltd/yuzu/performance"><img src="https://agentmods.dev/badge/agents/devnullltd/yuzu/performance.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 | $0.00013 | $0.00901 |
| Opus 5.5 | $0.00005 | $0.00360 |
| Sonnet 5.5 | $0.00003 | $0.00180 |
| Haiku 4.5 | $0.00001 | $0.00090 |
Grade A, and why
performance 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 27d 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.
The source is not reproduced here
Licensed AGPL-3.0
The repository is licensed AGPL-3.0, which this catalogue does not treat as permission to reproduce the file. Read it at the source.
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.
- 27d ago First seen · 81 lines · 13 tokens per session scan A 65d3f3db0b7a
performance is an agent published in the GitHub repository DevNullLtd/Yuzu (19 stars, last pushed today), licensed AGPL-3.0. It adds 13 tokens to every session and 901 once invoked, about $0.0001 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 2026-10-02.
Other agents, from other repositories
verifier
Use this agent when verifying that implementation meets success criteria, validating phase completion, checking plan coverage before execution, or performing pre-ship validation. Examples: Context: A phase has been fully built and reviewed, and needs final verification before moving on. user: "Verify that the database…
vibe-seed-check-worker
Checks the repository's vibe seed against fresh main for the vibe-seed-refresh orchestrator. Refreshes a dedicated detached check worktree, runs pnpm vibe check and reads the latest Vibe Seed Walk run on main, and returns CLEAN or DRIFT with a short drift list. Changes no tracked files.
business_logic
Produce testcases rows for an existing step-based YAML stub that cover IF/ELSE branches, CASE WHEN arms, happy paths, and error paths. Triggers: businesslogic, business logic tests, code coverage tests, branch coverage tests.
seed-generator
Test data generator. Creates realistic seed data based on schema.
command-repository-tests-implementer
Implements pytest integration tests for an aggregate's command-side repository. Invoke with: @command-repository-tests-implementer.
query-repository-tests-implementer
Implements pytest integration tests for an aggregate's query-side repository through the querycontext fixture. Invoke with: @query-repository-tests-implementer.