rca

rca is a skill for Claude Code from noordeen123/culprit. It costs 173 tokens per session (2,428 once invoked), scanned A, original, MIT.

A root-cause analysis and quality review tool for pull requests, branches, or stack traces. Root-cause analysis means finding why a problem happened, not just where it appeared.

In plain words
What is it for?
It helps identify suspect commits, explain why a bug broke, review its impact and release history, and assess whether the fix is complete.
Why use it?
It helps separate a bug fix from a feature change and traces bugs back through the commits that introduced and fixed them.

Skill for Claude Code

Written for Claude Code: Claude Code plugin machinery. Also seen: reads .claude/ paths; mentions Claude Code; mentions Codex.

Good fit It helps identify suspect commits, explain why a bug broke, review its impact and release history, and assess whether the fix is complete.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/noordeen123/culprit/claude-code-skill
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 noordeen123/culprit --skill claude-code-skill
Clone the repo
git clone --depth 1 https://github.com/noordeen123/culprit

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 rca

README.md
[![agentmods](https://agentmods.dev/badge/skills/noordeen123/culprit/claude-code-skill.svg)](https://agentmods.dev/skills/noordeen123/culprit/claude-code-skill)
Your own site
<a href="https://agentmods.dev/skills/noordeen123/culprit/claude-code-skill"><img src="https://agentmods.dev/badge/skills/noordeen123/culprit/claude-code-skill.svg" alt="Measured on agentmods" height="20"></a>
Per session 173 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,428 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 $0.00173 $0.02428
Opus 5 $0.00086 $0.01214
Sonnet 5 $0.00035 $0.00486
Haiku 4.5 $0.00017 $0.00243

Measured 8d ago against content hash 70c51ff38a13, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

rca 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 8d 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.

examples/claude-code-skill/SKILL.md · 164 lines

How it starts

The opening of the file, as written. The whole thing — 164 lines — stays where its author put it; the contents beside it link to each section on GitHub.

RCA (Root Cause Analysis) + QA review

Runs the deterministic culprit engine to produce a structured analysis + markdown skeleton, then you write the "why it broke" / risk narrative by reading the actual diffs of the suspect commits.

Invoking culprit (<RCA>)

  • Installed (pip install culprit): rca (or culprit).
  • From a checkout, no install: PYTHONPATH=/path/to/culprit python3 -m culprit.cli.

The examples below write <RCA> for whichever form you use, and --repo <REPO_PATH> (omit it when running from inside the repo - it defaults to the current directory).

Read the full file on GitHub · 164 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. 8d ago First seen · 164 lines · 173 tokens per session scan A 70c51ff38a13

Subscribe to this mod's changes

rca is a skill published in the GitHub repository noordeen123/culprit (6 stars, last pushed 12d ago), licensed MIT. It adds 173 tokens to every session and 2,428 once invoked, about $0.0009 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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