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mutsu: Skill for Claude Code

.agents/skills/perf-tuning/SKILL.md

perf-tuning is a skill for Claude Code, Codex from tokuhirom/mutsu. It costs 93 tokens per session (5,933 once invoked), scanned B, original, Artistic-2.0.

A performance-tuning procedure for the Mutsu project that measures code speed with profiling tools such as callgrind, a tool that records where a program spends time.

In plain words
What is it for?
Use it to investigate performance tasks, compare caller counts, and make a measured optimization.
Why use it?
It avoids misleading results caused by measuring warm and cold precompilation differently, and helps report improvements based on the right measurement.

Skill for Claude CodeCodex

Which agent this was written for is unclear — body not stored (licence); the path alone says nothing. Also seen: installed under .agents/ (shared by several agents).

This is tokuhirom/mutsu's own configuration. It tells Claude Code and Codex how to work on mutsu itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything mutsu configures →

not rated 30repo changed 1mo ago B scan 93 tokens Artistic-2.0
View source ↗ tokuhirom/mutsu tokuhirom.github.io
Reuse

Borrowing it

Nothing to install: this file belongs to tokuhirom/mutsu. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/tokuhirom/mutsu/main/.agents/skills/perf-tuning/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/tokuhirom/mutsu

Made for: Claude Code, Codex.

Wrote 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.

agentmods badge for perf-tuning

README.md
[![agentmods](https://agentmods.dev/badge/skills/tokuhirom/mutsu/perf-tuning/github.svg)](https://agentmods.dev/skills/tokuhirom/mutsu/perf-tuning)
Your own site
<a href="https://agentmods.dev/skills/tokuhirom/mutsu/perf-tuning"><img src="https://agentmods.dev/badge/skills/tokuhirom/mutsu/perf-tuning/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.

agentmods 80×15 button for perf-tuning

Your own site · 80×15
<a href="https://agentmods.dev/skills/tokuhirom/mutsu/perf-tuning"><img src="https://agentmods.dev/badge/skills/tokuhirom/mutsu/perf-tuning.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 93 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 5,933 The whole file, excluding the scripts and references it only reads on demand.
Security scan B 1 finding. A grade says what 26 rules found in the file — not that it is safe.
Origin unknown No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00093 $0.05933
Opus 5.5 $0.00037 $0.02373
Sonnet 5.5 $0.00019 $0.01187
Haiku 4.5 $0.00009 $0.00593

Measured 1mo ago against content hash 63ec512eb414, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade B, and why

perf-tuning scanned grade B with 1 finding 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.

The scan reads SKILL.md. This mod also ships 1 executable file (cg-summary.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

Asks for rootmediumPrivilege escalation

A mod that escalates privileges can change anything on the machine, not only the project.

sudo -n -l | grep perf # does the NOPASSWD path match `which perf`?
.agents/skills/perf-tuning/SKILL.md · 389 lines

The source is not reproduced here

Licensed Artistic-2.0

The repository is licensed Artistic-2.0, which this catalogue does not treat as permission to reproduce the file. Read it at the source.

Read it on GitHub

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

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.

  1. 1mo ago Changed · -3 lines 63ec512eb414
  2. 1mo ago Changed · +7 lines a395444b7a4e
  3. 1mo ago Changed · +5 lines d02b4e72dc2e
  4. 1mo ago Changed · +11 lines 59d3f24a8d7a
  5. 1mo ago Changed · +21 lines b150a7bce808
  6. 1mo ago Changed · +50 lines 93b5764765ee
  7. 1mo ago First seen · 298 lines · 93 tokens per session scan B 0f13e34adc21

Subscribe to this mod's changes

perf-tuning is a skill published in the GitHub repository tokuhirom/mutsu (30 stars, last pushed today), licensed Artistic-2.0. It adds 93 tokens to every session and 5,933 once invoked, about $0.0004 per session on Opus 5.5. A static security scan graded it B with 1 finding (asks for root). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-21.

Analytics and metricsDebugging
Related

perf-tuning compared with skills from other repositories

perf-tuning next to 6 skills from other repositories
ModTypeStarsLast pushLicenceScanTokensWorks with
perf-tuningtokuhirom/mutsuSkill30todayArtistic-2.0B93Claude Code, Codex
systematic-debuggingopen-metadata/OpenMetadataSkill16kyesterdayApache-2.0A37Claude Code
log-error-digestzebbern/claude-code-guideSkill4.7k3d agoMITA71Claude Code, Codex
cwv-optimizeradobe/skillsSkill319yesterdayApache-2.0A112Claude Code
ci-fixersipyourdrink-ltd/bernsteinSkill1.2kyesterdayApache-2.0A15Claude Code, Codex
incident-response-incident-responsermyndharis/antigravity-skillsSkill1.9k23d agoMITA36Claude Code
triaging-web-analytics-supportPostHog/posthogSkill41kyesterdaynoneA151Claude Code, Codex