bike_index: Skill for Claude Code

.claude/skills/skill-creator/SKILL.md

skill-creator is a skill for Claude Code from bikeindex/bike_index. It costs 64 tokens per session (7,295 once invoked), scanned A, original, AGPL-3.0.

A toolkit for creating, editing, testing, and improving coding-agent skills. It also helps measure how well a skill works and how reliably the agent selects it.

In plain words
What is it for?
Use it to build a skill from scratch, revise its instructions, run evaluations, compare results, and improve its activation wording.
Why use it?
It gives skill authors a repeatable way to check whether instructions work and improve them when they do not.

Skill for Claude Code

Written for Claude Code: installed under .claude/.

This is bikeindex/bike_index's own configuration. It tells Claude Code how to work on bike_index itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything bike_index configures →

Reuse

Borrowing it

Nothing to install: this file belongs to bikeindex/bike_index. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/bikeindex/bike_index/main/.claude/skills/skill-creator/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/bikeindex/bike_index

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 skill-creator

README.md
[![agentmods](https://agentmods.dev/badge/skills/bikeindex/bike_index/skill-creator/github.svg)](https://agentmods.dev/skills/bikeindex/bike_index/skill-creator)
Your own site
<a href="https://agentmods.dev/skills/bikeindex/bike_index/skill-creator"><img src="https://agentmods.dev/badge/skills/bikeindex/bike_index/skill-creator/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 skill-creator

Your own site · 80×15
<a href="https://agentmods.dev/skills/bikeindex/bike_index/skill-creator"><img src="https://agentmods.dev/badge/skills/bikeindex/bike_index/skill-creator.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 64 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 7,295 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. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 1 finding, up to medium

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • medium Rogue Agent · line 240
    Skill establishes unauthorized persistence across sessions via cron jobs, startup scripts, or state files. Session persistence allows an attacker to maintain access beyond the current interaction.
    Fix: Remove any persistence mechanisms (cron jobs, startup scripts, state files). Skills should not maintain state across sessions without explicit user consent.
How audits are shown
Origin unknown 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 $0.00064 $0.07295
Opus 5 $0.00032 $0.03648
Sonnet 5 $0.00013 $0.01459
Haiku 4.5 $0.00006 $0.00730

Measured 8d ago against content hash c2cd7cc5dd19, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

skill-creator 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.

The scan reads SKILL.md. This mod also ships 10 executable files (eval-viewer/generate_review.py, scripts/__init__.py, scripts/aggregate_benchmark.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.

.claude/skills/skill-creator/SKILL.md · 488 lines

The source is not reproduced here

Licensed AGPL-3.0

The repository is licensed AGPL-3.0, which this catalogue does not treat as permission to reproduce the file. Read it at the source.

Read it on GitHub

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 · 488 lines · 64 tokens per session scan A c2cd7cc5dd19

Subscribe to this mod's changes

skill-creator is a skill published in the GitHub repository bikeindex/bike_index (309 stars, last pushed today), licensed AGPL-3.0. It adds 64 tokens to every session and 7,295 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 2026-09-03.

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