hotspots

hotspots is a skill for Claude Code from lexler/skill-factory. It costs 57 tokens per session (1,115 once invoked), scanned A, original, Apache-2.0.

A Git-history analysis finds files that are both complex and changed often. It ranks likely refactoring targets and shows which files tend to change together.

In plain words
What is it for?
Use it to inspect a repository or part of a monorepo, find high-priority files, study change relationships, and check whether a past refactoring reduced hotspots.
Why use it?
It helps you choose refactoring work from evidence instead of guessing from the current code alone. It can also identify code that should be left alone because it is stable.

Skill for Claude Code

Written for Claude Code: disable-model-invocation in frontmatter.

Good fit Use it to inspect a repository or part of a monorepo, find…

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Install with agentmods
npx agentmods add skills/lexler/skill-factory/hotspots
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 lexler/skill-factory --skill hotspots
Clone the repo
git clone --depth 1 https://github.com/lexler/skill-factory

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 hotspots

README.md
[![agentmods](https://agentmods.dev/badge/skills/lexler/skill-factory/hotspots.svg)](https://agentmods.dev/skills/lexler/skill-factory/hotspots)
Your own site
<a href="https://agentmods.dev/skills/lexler/skill-factory/hotspots"><img src="https://agentmods.dev/badge/skills/lexler/skill-factory/hotspots.svg" alt="Measured on agentmods" height="20"></a>
Per session 57 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,115 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 $0.00057 $0.01115
Opus 5 $0.00028 $0.00558
Sonnet 5 $0.00011 $0.00223
Haiku 4.5 $0.00006 $0.00112

Measured 7d ago against content hash c2b036cd9899, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

hotspots 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 7d ago.

The scan reads SKILL.md. This mod also ships 3 executable files (scripts/coupling.py, scripts/gitlog.py, scripts/mine.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.

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.

output_skills/practices/hotspots/SKILL.md · 70 lines

How it starts

The opening of the file, as written. The whole thing — 70 lines — stays where its author put it; the contents beside it link to each section on GitHub.

STARTER_CHARACTER = 🔥

Hotspot analysis ranks files by change frequency × complexity. Code that is both complicated and changed often is where refactoring pays; complicated but stable code is not — "if it never changes, it's not costing us money." The scripts compute every number deterministically; your job is scoping, validation, and interpretation. A hotspot is a pointer to where to look, never a diagnosis.

If the user wants to check whether a past refactoring paid off and hotspots/data/mine.json exists in the repo, jump to VERIFY. Otherwise run the steps in order.

1. SCOPE

Decide and record:

  • Window: default 12 months; use "since last major release" if the user names one. Under ~6 months of history, warn that rankings are unreliable.
  • Target: repo root, or the subtree the user cares about in a monorepo.
  • Extra excludes: skim the tree for generated/vendored content the defaults miss (see default list in scripts/mine.py). Keep test files in — a test file as top hotspot is a real and common finding.
  • History quality: if most commits are PR squashes, note that coupling signal is weakened.

Done when window, target, and extra excludes are chosen and any history caveats are noted for the report header.

2. MINE

uv run ${CLAUDE_SKILL_DIR}/scripts/mine.py <repo> --months <N> [--exclude PATTERN]... --out hotspots/data/mine.json
uv run ${CLAUDE_SKILL_DIR}/scripts/coupling.py <repo> --months <N> [--exclude PATTERN]... --out hotspots/data/coupling.json

Pass the same --months and --exclude flags to both. If summary.warnings reports too few commits or nothing ranked, widen the window or lower --min-revs and re-run.

Done when both JSON files exist and files_ranked > 0.

3. VALIDATE

Take the top ~10 files by score from mine.json. Read each one and give a verdict — confirmed hotspot, or discarded with the false-positive class it belongs to (catalog in references/interpretation.md). When discards free up slots, pull in the next candidates so ~10 get verdicts.

Read the full file on GitHub · 70 lines

Files

What ships with it

4 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. 7d ago First seen · 70 lines · 57 tokens per session scan A c2b036cd9899

Subscribe to this mod's changes

hotspots is a skill published in the GitHub repository lexler/skill-factory (233 stars, last pushed 11d ago), licensed Apache-2.0. It adds 57 tokens to every session and 1,115 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 2026-08-30.

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