szz-bug-introducing-commit-identifier

szz-bug-introducing-commit-identifier is a skill for Claude Code, Codex from ArabelaTso/Skills-4-SE. It costs 121 tokens per session (1,365 once invoked), scanned A, original, Apache-2.0.

A Git-history analysis tool that traces a bug-fixing change back to commits that may have introduced the bug. SZZ uses line history and code blame to identify possible originating commits.

In plain words
What is it for?
Use it to analyse bug-fixing commits, rank likely bug-introducing commits, and support software repository history investigations.
Why use it?
It helps teams investigate when and where a defect entered a repository instead of looking only at the final fix.

Skill for Claude CodeCodex

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

Good fit Use it to analyse bug-fixing commits, rank likely bug-introducing commits, and support software repository history investigations.

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Install with agentmods
npx agentmods add skills/arabelatso/skills-4-se/szz-bug-identifier
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 ArabelaTso/Skills-4-SE --skill szz-bug-identifier
Clone the repo
git clone --depth 1 https://github.com/ArabelaTso/Skills-4-SE

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 szz-bug-introducing-commit-identifier

README.md
[![agentmods](https://agentmods.dev/badge/skills/arabelatso/skills-4-se/szz-bug-identifier/github.svg)](https://agentmods.dev/skills/arabelatso/skills-4-se/szz-bug-identifier)
Your own site
<a href="https://agentmods.dev/skills/arabelatso/skills-4-se/szz-bug-identifier"><img src="https://agentmods.dev/badge/skills/arabelatso/skills-4-se/szz-bug-identifier/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 szz-bug-introducing-commit-identifier

Your own site · 80×15
<a href="https://agentmods.dev/skills/arabelatso/skills-4-se/szz-bug-identifier"><img src="https://agentmods.dev/badge/skills/arabelatso/skills-4-se/szz-bug-identifier.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 121 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,365 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
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 $0.00121 $0.01365
Opus 5 $0.00060 $0.00682
Sonnet 5 $0.00024 $0.00273
Haiku 4.5 $0.00012 $0.00136

Measured 8d ago against content hash 111025974e9e, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

szz-bug-introducing-commit-identifier scanned grade A with 1 finding 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.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/szz_analyzer.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

Runs shell commandslowCapability

Expected in a hook, worth knowing in a rule or an instructions file.

result = subprocess.run(
skills/szz-bug-identifier/SKILL.md · 183 lines

How it starts

The opening of the file, as written. The whole thing — 183 lines — stays where its author put it; the contents beside it link to each section on GitHub.

SZZ Bug-Introducing Commit Identifier

Overview

This skill performs SZZ (Śliwerski-Zimmermann-Zeller) algorithm analysis to identify bug-introducing commits in git repositories. Given a bug-fixing commit, it traces modified lines back through version history using git blame to find candidate commits that originally introduced the buggy code.

Workflow

1. Identify the Bug-Fixing Commit

Start by identifying the commit that fixes the bug. This can be obtained from:

  • Commit hash provided by the user
  • Issue tracker references (e.g., "fixes #123")
  • Commit message analysis (e.g., "fix:", "bug:")
  • Manual identification by the user

2. Run the SZZ Analysis

Use the provided script to perform the analysis:

python scripts/szz_analyzer.py <fix-commit-hash>

Options:

  • --repo <path>: Specify repository path (default: current directory)
  • --json: Output results in JSON format for programmatic processing
  • --top <n>: Number of top candidates to show (default: 10)

Example:

python scripts/szz_analyzer.py abc123def --repo /path/to/repo --top 5

3. Interpret Results

The script outputs a ranked list of candidate bug-introducing commits with:

  • Commit hash: The candidate commit identifier
  • Author: Who made the commit
  • Date: When the commit was made
  • Message: The commit message
  • Confidence score: Likelihood this commit introduced the bug (0.0-1.0)
  • Reasons: Explanation for why this commit is a candidate

4. Manual Verification

Always manually review the top candidates:

  1. Examine the actual code changes in the candidate commit
  2. Check if the changes are functionally related to the bug
  3. Consider the context and purpose of the changes
  4. Verify against issue tracker history if available

Understanding Confidence Scores

High Confidence (0.8-1.0):

  • Multiple lines from the commit were fixed
  • Commit message doesn't suggest refactoring
  • Functional code changes (not just formatting)

Read the full file on GitHub · 183 lines

Files

What ships with it

2 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.

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 · 183 lines · 121 tokens per session scan A 111025974e9e

Subscribe to this mod's changes

szz-bug-introducing-commit-identifier is a skill published in the GitHub repository ArabelaTso/Skills-4-SE (252 stars, last pushed 22d ago), licensed Apache-2.0. It adds 121 tokens to every session and 1,365 once invoked, about $0.0006 per session on Opus 5. A static security scan graded it A with 1 finding (runs shell commands). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.

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