debug

A root-cause debugging route investigates an observed error, crash, regression, failing test, or intermittent behavior before code is changed.

In plain words
What is it for?
Use it to reproduce failures, identify the responsible file and function, fix the cause, run a check that could still fail, and look for similar bugs elsewhere.
Why use it?
It prevents guessing at fixes by requiring a specific cause, a reproducible check, and verification that related instances were also considered.

Skill for Claude CodeCodex

Install

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.

agentmods
npx agentmods add skills/panda850819/verbs/debug
Any agent
npx skills add panda850819/verbs --skill debug
Clone the repo
git clone --depth 1 https://github.com/panda850819/verbs

Made for: Claude Code, Codex.

Per session 74 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 535 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original 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 $0.00074 $0.00535
Opus 5 $0.00037 $0.00267
Sonnet 5 $0.00015 $0.00107
Haiku 4.5 $0.00007 $0.00053

Measured yesterday against content hash 66ca58e2f645, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

debug 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 yesterday.

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.

skills/engineering/debug/SKILL.md · 40 lines

What it actually says

Debug

You already know how to debug. This skill is not the method. It overrides the momentum reflexes you get wrong and points you to lore you cannot derive.

Override

  • Name the root cause before you edit. At file:function:line, with the evidence. "A state issue" is not a root cause; "stale cache in useUser at user.ts:42, dep array missing userId" is. Editing before you can say that sentence is the failure mode.
  • Diagnosis ends only on a red-capable command. Name one already-run deterministic, fast, agent-runnable command that can fail, and say you saw its output. "I understand the bug" is not done.
  • Do not claim fixed until you ran it and looked. "Should work" is not evidence. Compile-only is not enough for UI / native / generated-artifact bugs: open it, and for generated output read the contents, not the source diff. Cannot run it here → say so and hand off the exact check.
  • Before "fixed", grep the signature for siblings. One fix that ignores siblings leaves N-1 in the tree; the same shape usually hides elsewhere.

Lore (consult when the cause is not obvious)

lib/diagnosis.md — known bug classes (listener-owns-lifetime, O(N²) accumulators, schema category-leak, and CLI archetypes: PATH drift, stdout/stderr contract, pipe backpressure, cold-start), instrument-first-by-bug-class, bisect with worktree safety, and the 3-failed-hypotheses handoff template.

Recall first per @lib/learning-recall.md: pull from the repo learning path configured by the host project, matching the symptom / bug class before hypothesizing. A new reusable bug class emits a candidate using lib/learning-format.md; a match emits a one-line seen again candidate. Never write or update the learning store here. Persistence belongs to the host/project.

Files

What ships with it

4 files 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. yesterday First seen · 40 lines · 74 tokens per session scan A 66ca58e2f645

Subscribe to this mod's changes

debug is a skill published in the GitHub repository panda850819/verbs (5 stars, last pushed 9d ago), licensed MIT. It adds 74 tokens to every session and 535 once invoked, about $0.0004 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 2026-08-31.

Related

Other skills, from other repositories

processing-markdown

Processes Markdown files using mq, a jq-like query language for Markdown. Use when the user mentions Markdown processing, content extraction, document transformation, or mq queries.

harehare/mq · 36 tokens

markstream-react

Integrate the beta markstream-react package into a React 18+ or Next app. Use when Codex needs to add the React renderer, choose the root, next, or server entrypoint, import CSS correctly, choose between content and nodes, keep client boundaries safe, add renderer-local streamingComponents or htmlComponents, use…

Simon-He95/markstream-vue · 94 tokens

web-scraping

Fetches web pages and extracts structured data using mq's toolchain (mq-crawl for fetching/crawling/JS rendering, mq for HTML-to-Markdown selector-based extraction, http() for in-query requests). Use when the user wants to scrape a URL, pull structured data out of a webpage, crawl a site, or turn HTML into…

harehare/mq · 89 tokens

markstream-vue2-cli

Integrate markstream-vue2 into a Vue 2 Vue CLI or Webpack 4 app. Use when Codex needs Webpack 4-friendly setup, CDN worker fallbacks for Mermaid or KaTeX, dist/index.css imports, Vue 2 composition-api shims, or code block choices limited to stream-diffs or plain .

Simon-He95/markstream-vue · 83 tokens

markstream-svelte

Integrate the beta markstream-svelte package in Svelte 5 or SvelteKit apps. Use when Codex needs Svelte 5 runes, CSS and optional peers, smooth streaming, worker setup, renderer-local or scoped custom components, or SSR-safe boundaries. Svelte 4 is unsupported.

Simon-He95/markstream-vue · 67 tokens

decided-import

Reformat ONE existing document (a decision, requirement, design, roadmap, or prompt) into ONE valid RAC (requirements-as-code) artifact, with a mandatory human-review step before any file is written and decided validate as the deterministic close. Use when a user wants to add or import a single existing decision or…

asdecided/core · 98 tokens