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.
npx skills add Cristhianzl/claude-skills-czl --skill fixing-bugsgit clone --depth 1 https://github.com/Cristhianzl/claude-skills-czlWrote 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/skills/cristhianzl/claude-skills-czl/fixing-bugs)<a href="https://agentmods.dev/skills/cristhianzl/claude-skills-czl/fixing-bugs"><img src="https://agentmods.dev/badge/skills/cristhianzl/claude-skills-czl/fixing-bugs/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/skills/cristhianzl/claude-skills-czl/fixing-bugs"><img src="https://agentmods.dev/badge/skills/cristhianzl/claude-skills-czl/fixing-bugs.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 | $0.00105 | $0.02844 |
| Opus 5 | $0.00053 | $0.01422 |
| Sonnet 5 | $0.00021 | $0.00569 |
| Haiku 4.5 | $0.00011 | $0.00284 |
Grade A, and why
fixing-bugs 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 12d 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.
How it starts
The opening of the file, as written. The whole thing — 235 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Fixing Bugs
Never fix a bug before proving it exists with a failing test. The fix is only valid if a test transitions from RED (failing) to GREEN (passing).
Read first (always)
List learnings/ and read every file relevant to the current bug. Project-specific test conventions, framework quirks, recurring bug patterns, or hot zones live there and override the defaults in this SKILL.md. If a learning conflicts with this file, the learning wins — mention it to the user.
Tradeoff — when to apply, when to lighten up
Apply the full cycle for any defect in production code the user is reporting (Sentry alert, support ticket, "this broke", regression). The discipline pays off because the test becomes a permanent sentinel against the same bug returning.
Lighten the formality only when fixing a typo, a build script, or a one-off script the user explicitly labels as throwaway. Even then, run the test suite afterwards.
The cycle (strict order)
1. UNDERSTAND → Read the bug report; identify expected vs actual; locate the OS/platform
2. REPRODUCE → Write a failing test that triggers the EXACT error path
3. VERIFY RED → Run the test; it MUST fail for the reason in the bug report
4. FIX → Write the MINIMUM code change to make the test pass
5. VERIFY GREEN → Run the same test; it MUST now pass
6. VALIDATE → Run the FULL suite (CI matrix if platform-suspect); nothing else breaks
7. REFACTOR → Optional; only if the fix introduced duplication. Tests stay GREEN
If you skip steps or change the order, the fix is invalid. Full per-phase detail in references/cycle.md.
Phase 1 — UNDERSTAND
Decompose the bug report:
GIVEN: <precondition / initial state>
WHEN: <action that triggers the bug>
THEN: <what actually happens — the bug>
EXPECTED: <what should happen — the fix target>
If you can't extract all four → ask for clarification, don't guess.
Identify the platform dimension. Bug reports rarely state the OS. Check user agent, Sentry tags, container image, support metadata. Bugs in the following areas are platform-suspect by default — filesystem operations, text encoding / line endings, subprocess / shell, temp / config dir resolution, process signals, networking. If the bug is platform-suspect, the test must run on the affected OS in Phase 3.
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.
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.
- 12d ago First seen · 235 lines · 105 tokens per session scan A 7e96a383e33f
fixing-bugs is a skill published in the GitHub repository Cristhianzl/claude-skills-czl (5 stars, last pushed yesterday), licensed MIT. It adds 105 tokens to every session and 2,844 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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