A debugging guide for mutsu, focused on inspecting syntax trees, tracing execution, using Rust's debugger, and running focused unit tests instead of repeatedly adding print statements and rebuilding.

Investigating mutsu behavior with AST dumps, MUTSUTRACE, scripted rust-gdb breakpoints, and focused Rust tests.

It provides a repeatable way to discover which code path ran or changed a value without relying on ad hoc logging.

How tokuhirom/mutsu configures Claude Code and Codex

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/debugging/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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/tokuhirom/mutsu/debugging/github.svg)](https://agentmods.dev/skills/tokuhirom/mutsu/debugging)

Your own site

<a href="https://agentmods.dev/skills/tokuhirom/mutsu/debugging"><img src="https://agentmods.dev/badge/skills/tokuhirom/mutsu/debugging/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.

Your own site · 80×15

<a href="https://agentmods.dev/skills/tokuhirom/mutsu/debugging"><img src="https://agentmods.dev/badge/skills/tokuhirom/mutsu/debugging.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 66 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 1,119 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. 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.

Model	Per session	Once invoked
Fable 5.1	$0.00066	$0.01119
Opus 5.5	$0.00026	$0.00448
Sonnet 5.5	$0.00013	$0.00224
Haiku 4.5	$0.00007	$0.00112

Measured 1mo ago against content hash 911a3fb8184b, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

debugging 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 1mo 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.

.agents/skills/debugging/SKILL.md · 68 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

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.

1mo ago First seen · 68 lines · 66 tokens per session scan A 911a3fb8184b

Subscribe to this mod's changes

debugging is a skill published in the GitHub repository tokuhirom/mutsu (30 stars, last pushed today), licensed Artistic-2.0. It adds 66 tokens to every session and 1,119 once invoked, about $0.0003 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 2026-09-26.

Debugging Languages Rust

debugging next to 6 skills from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
debuggingtokuhirom/mutsu	Skill	30	today	Artistic-2.0	A	66	Claude Code, Codex
rust-checkHmbown/CodeWhale	Skill	41k	5d ago	MIT	A	15	Claude Code, Codex
stack-trace-rust-probeopensquilla/opensquilla	Skill	7.1k	6d ago	Apache-2.0	A	42	Claude Code
hotpath_initpawurb/hotpath-rs	Skill	1.9k	19d ago	MIT	A	88	Claude Code
rust-errorBerriAI/litellm	Skill	63k	yesterday	none	A	72	Claude Code, Codex
rust-tracingBerriAI/litellm	Skill	63k	yesterday	none	A	28	Claude Code, Codex
clickhouse-rust-type-mismatchesdivinevideo/divine-mobile	Skill	264	yesterday	MPL-2.0	A	280	Claude Code, Codex

mutsu: Skill for Claude Code