bisect-regression

A Git procedure for finding the exact commit that introduced a bug.

In plain words
What is it for?
Use it when software worked before, broke after later changes, and you have a small test or script that can distinguish the working and broken states.
Why use it?
It replaces guesswork with repeated checks between a known-working and known-broken version until Git identifies the first bad change.

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/archive228/loopkit/bisect-regression
Any agent
npx skills add Archive228/loopkit --skill bisect-regression
Clone the repo
git clone --depth 1 https://github.com/Archive228/loopkit

Made for: Claude Code, Codex.

Per session 0 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 209 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 $0.00000 $0.00209
Opus 5 $0.00000 $0.00105
Sonnet 5 $0.00000 $0.00042
Haiku 4.5 $0.00000 $0.00021

Measured 2d ago against content hash 52678b255c45, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

bisect-regression 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/bisect-regression/SKILL.md · 13 lines

What it actually says

Bisect the Regression

  1. Find a known-good commit and a known-bad one. Confirm both by actually checking out and testing.
  2. git bisect start; git bisect bad <bad>; git bisect good <good>.
  3. At each step, run the SMALLEST test that distinguishes good from bad. Mark git bisect good/bad.
  4. When git names the first bad commit, read its diff. The bug is in those lines — don't guess elsewhere.
  5. git bisect reset. Report: the commit, the line, the one-sentence cause. Automate it: git bisect run ./repro.sh if you have a script that exits non-zero on the bug.
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 · 13 lines · 0 tokens per session scan A 52678b255c45

Subscribe to this mod's changes

bisect-regression is a skill published in the GitHub repository Archive228/loopkit (753 stars, last pushed 1mo ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 209 tokens. 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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