C31-workflow-bug-reproduction

C31-workflow-bug-reproduction is a skill for Claude Code, Codex from ChianW/C31. It costs 53 tokens per session (607 once invoked), scanned A, original, MIT.

A read-only workflow for systematically reproducing and isolating software bugs. It turns a vague report into a small, verifiable example and checks whether the cause is in the code, environment, or configuration.

In plain words
What is it for?
Use it when reproduction steps are missing, a regression test may be needed, or a bug might depend on CI, production, versions, or configuration.
Why use it?
It helps identify why a problem occurs without changing the code while investigating it.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it when reproduction steps are missing, a regression test may be needed, or a bug might depend on CI, production, versions, or configuration.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/chianw/c31/c31-workflow-bug-reproduction
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 ChianW/C31 --skill c31-workflow-bug-reproduction
Clone the repo
git clone --depth 1 https://github.com/ChianW/C31

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.

agentmods badge for C31-workflow-bug-reproduction

README.md
[![agentmods](https://agentmods.dev/badge/skills/chianw/c31/c31-workflow-bug-reproduction/github.svg)](https://agentmods.dev/skills/chianw/c31/c31-workflow-bug-reproduction)
Your own site
<a href="https://agentmods.dev/skills/chianw/c31/c31-workflow-bug-reproduction"><img src="https://agentmods.dev/badge/skills/chianw/c31/c31-workflow-bug-reproduction/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.

agentmods 80×15 button for C31-workflow-bug-reproduction

Your own site · 80×15
<a href="https://agentmods.dev/skills/chianw/c31/c31-workflow-bug-reproduction"><img src="https://agentmods.dev/badge/skills/chianw/c31/c31-workflow-bug-reproduction.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 53 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 607 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 $0.00053 $0.00607
Opus 5 $0.00026 $0.00303
Sonnet 5 $0.00011 $0.00121
Haiku 4.5 $0.00005 $0.00061

Measured 9d ago against content hash 9abacde2a0da, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

C31-workflow-bug-reproduction 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 9d 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/core/C31-workflow-bug-reproduction/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.

Multilingual Triggers

Language Trigger phrases
EN C31-workflow-bug-reproduction
ZH 复现bug, bug复现
JA バグ再現, 再現手順

Output language: Respond automatically in the user's conversation language.

C31-workflow-bug-reproduction

Systematic bug reproduction and isolation. Read-only — never writes code.

When to Use

  • Bug report lacks clear reproduction steps
  • Need to determine if bug is environmental or code-level
  • Creating a regression test for a reported issue
  • Bug only appears in CI/production but not locally
  • User says "it doesn't work" without specifics

Input

User provides:

  • Bug symptom (what's wrong)
  • Environment where it occurs (OS, versions, config)
  • Any existing reproduction steps (even partial)
  • Whether it reproduces consistently or intermittently

Reproduction Flow

  1. Form hypotheses — List 3 likely causes ranked by probability:

    • Code bug (logic error, race condition)
    • Environment issue (wrong version, missing dependency, stale state)
    • Config issue (wrong flag, missing env var)
  2. Minimize surface area:

    • Strip unrelated code/config
    • Use minimal dataset
    • Disable caching, async, or concurrency if possible
    • Test with defaults before custom config
  3. Controlled experiments:

    • Change one variable at a time
    • Document each result
    • If intermittent, run N times and log frequency
  4. Verify reproduction:

    • Reproduces on clean environment? → code bug
    • Only reproduces on specific env? → environment/config bug
    • Doesn't reproduce at all? → missing condition or fixed already

Output Format

## Bug Reproduction: [brief description]
**Hypotheses tested**:
| # | Hypothesis | Result | Evidence |
**Minimal reproduction**:
[steps or code that reliably triggers the bug]
**Root cause category**: [code / environment / config / cannot reproduce]
**Additional conditions required**: [if any]
**Recommended next step**: [fix / deeper investigation / environment change]

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. 9d ago First seen · 82 lines · 53 tokens per session scan A 9abacde2a0da

Subscribe to this mod's changes

C31-workflow-bug-reproduction is a skill published in the GitHub repository ChianW/C31 (1 stars, last pushed 14d ago), licensed MIT. It adds 53 tokens to every session and 607 once invoked, about $0.0003 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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