Debugging Playbook

Debugging Playbook is a skill for Claude Code from ralfyishere/rules-with-receipts. It costs 99 tokens per session (1,675 once invoked), scanned A, original, MIT.

A step-by-step method for finding the cause of broken, failing, or unexpected software behavior. It moves from the symptom and a reproducible case through hypotheses and targeted tests to a verified fix and regression test.

In plain words
What is it for?
Use it for error messages, failing tests, crashes, hangs, incorrect output, performance regressions, intermittent failures, and similar problems outside code.
Why use it?
It replaces guess-and-check fixes with evidence, making it easier to isolate the real cause and avoid introducing more problems.

Skill for Claude Code

Written for Claude Code: installed under .claude/.

Good fit Use it for error messages, failing tests, crashes, hangs, incorrect output, performance regressions, intermittent failures, and similar problems outside code.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/ralfyishere/rules-with-receipts/debugging-playbook
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.

Any agent
npx skills add ralfyishere/rules-with-receipts --skill debugging-playbook
Clone the repo
git clone --depth 1 https://github.com/ralfyishere/rules-with-receipts

Made for: Claude Code.

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 Debugging Playbook

README.md
[![agentmods](https://agentmods.dev/badge/skills/ralfyishere/rules-with-receipts/debugging-playbook.svg)](https://agentmods.dev/skills/ralfyishere/rules-with-receipts/debugging-playbook)
Your own site
<a href="https://agentmods.dev/skills/ralfyishere/rules-with-receipts/debugging-playbook"><img src="https://agentmods.dev/badge/skills/ralfyishere/rules-with-receipts/debugging-playbook.svg" alt="Measured on agentmods" height="20"></a>
Per session 99 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,675 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 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 5.1 $0.00099 $0.01675
Opus 5 $0.00049 $0.00838
Sonnet 5 $0.00020 $0.00335
Haiku 4.5 $0.00010 $0.00168

Measured 7d ago against content hash 8508668aa8e5, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

Debugging Playbook 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 7d 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.

.claude/skills/debugging-playbook/SKILL.md · 82 lines

How it starts

The opening of the file, as written. The whole thing — 82 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Debugging Playbook

Purpose

Replace guess-and-check with evidence-and-elimination. Unstructured debugging is a random walk: plausible fixes applied to unconfirmed causes, each failed attempt polluting the state for the next. The playbook's core rule: you have found the root cause when you can predict the system's behavior — before and after the fix — and be right.

When to use this skill

  • Anything broken, failing, or surprising: errors, test failures, wrong output, crashes, hangs, performance drops.
  • "It worked before" situations — these are diffing problems in disguise.
  • Non-code failures with the same shape: a spreadsheet total that's off, a pipeline producing bad rows, a prompt whose outputs degraded.
  • Intermittent problems — especially these; guessing is uniquely useless against nondeterminism.

When NOT to use this skill

  • The cause is already proven and trivial (the error message names the missing import). Fix it; ceremony adds nothing.
  • Nothing is broken — for "could this break?" work, use failure-mode-awareness.
  • Building new things — that's plan-gate/deep-decomposition territory, even if motivated by a bug.

Operating procedure

1 — Capture the symptom, verbatim. Full error text, exact command, exact input, environment. "Something about a timeout" is not a symptom. Note what correct behavior would look like — surprising numbers of debugging sessions chase behavior that was actually fine.

2 — Reproduce it. Find the smallest, fastest, most deterministic reproduction you can. Every minute invested here is repaid at every hypothesis test. If you cannot reproduce: don't guess-fix — instrument (logging, counters, capture-on-failure) and wait for the next occurrence, or hunt for the missing trigger condition (timing, data, environment).

  • For "worked yesterday": diff the worlds. What changed between then and now — code, data, dependencies, config, environment? git log / deploy history / dependency lockfile first.

3 — Generate 2–4 ranked hypotheses. Rank by likelihood × cheapness-to-test. Sources: the error itself (read all of it), the diff since it last worked, the failure catalogs in failure-mode-awareness, and where this class of bug usually lives.

Read the full file on GitHub · 82 lines

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. 7d ago First seen · 82 lines · 0 tokens per session scan A 8508668aa8e5

Subscribe to this mod's changes

Debugging Playbook is a skill published in the GitHub repository ralfyishere/rules-with-receipts (2 stars, last pushed 1mo ago), licensed MIT. It adds 99 tokens to every session and 1,675 once invoked, about $0.0005 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.

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