bug-fix

A bug-fixing workflow that uses a test-first approach: first writing a test that reproduces the problem, then applying a focused fix and running checks for regressions.

In plain words
What is it for?
Use it for code, API, background-job, build, and interface bugs; interface bugs can also receive browser-based verification.
Why use it?
The reproducing test shows the bug is real and remains as protection against it returning. Running the existing tests helps detect accidental breakage elsewhere.

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/undeadlist/claude-code-agents/bug-fix
Any agent
npx skills add undeadlist/claude-code-agents --skill bug-fix
Clone the repo
git clone --depth 1 https://github.com/undeadlist/claude-code-agents

Made for: Claude Code, Codex.

Per session 13 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 304 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 $0.00013 $0.00304
Opus 5 $0.00006 $0.00152
Sonnet 5 $0.00003 $0.00061
Haiku 4.5 $0.00001 $0.00030

Measured 2d ago against content hash c785a02fcc24, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

bug-fix 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 2d 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.

skills/bug-fix/SKILL.md · 54 lines

What it actually says

Bug Fix Workflow

Fix bugs with a test-first approach to prevent regressions. Provide the bug description when invoking.

Execution (Sequential)

Step 1: Reproduce with Test

Spawn test-writer with the bug description:

  • Create a test that fails (reproduces the bug)
  • Test should pass after the fix is applied

Step 2: Fix the Bug

Spawn code-fixer with the bug description and test file:

  • Find root cause
  • Implement minimal fix
  • Don't refactor unrelated code

Step 3: Verify

Spawn test-runner:

  • New test passes (bug is fixed)
  • All existing tests pass (no regressions)

Step 4: Browser QA (if UI bug)

Spawn browser-qa-agent:

  • Reproduce original steps
  • Confirm bug is fixed
  • Check related features still work

Usage

Provide bug details when invoking:

/bug-fix

Bug: Login fails with valid credentials
Steps to reproduce:
1. Go to /login
2. Enter valid email/password
3. Click submit
Expected: Redirect to dashboard
Actual: 500 error
Location: src/api/auth/login.ts

Skip browser-qa for

  • Non-UI bugs (API, background jobs)
  • Build/compilation issues
  • Test infrastructure bugs
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. 2d ago First seen · 54 lines · 13 tokens per session scan A c785a02fcc24

Subscribe to this mod's changes

bug-fix is a skill published in the GitHub repository undeadlist/claude-code-agents (147 stars, last pushed 2mo ago), licensed MIT. It adds 13 tokens to every session and 304 once invoked, about $0.0001 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 2026-08-30.

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