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.
npx agentmods add skills/dwmkerr/claude-toolkit/skill-developmentnpx skills add dwmkerr/claude-toolkit --skill skill-developmentgit clone --depth 1 https://github.com/dwmkerr/claude-toolkitWrote 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.
[](https://agentmods.dev/skills/dwmkerr/claude-toolkit/skill-development)<a href="https://agentmods.dev/skills/dwmkerr/claude-toolkit/skill-development"><img src="https://agentmods.dev/badge/skills/dwmkerr/claude-toolkit/skill-development.svg" alt="Measured on agentmods" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5 | $0.00082 | $0.01348 |
| Opus 5 | $0.00041 | $0.00674 |
| Sonnet 5 | $0.00016 | $0.00270 |
| Haiku 4.5 | $0.00008 | $0.00135 |
Grade A, and why
claude-code-skill-development 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 4d 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.
How it starts
The opening of the file, as written. The whole thing — 158 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Skill Development
Create effective Claude Code skills that are concise, discoverable, and well-structured.
Quick Reference
You MUST read these references for detailed guidance:
- Best Practices - Official Anthropic guidance
- Skill Examples - Patterns from real skills
- Skill Categories & Patterns - Three categories and five reusable patterns
- Testing Guide - Triggering, functional, and performance testing
- Troubleshooting - Common problems and fixes
- The Complete Guide to Building Skills for Claude - Comprehensive Anthropic guide (source PDF)
Before You Start
Define 2-3 concrete use cases before writing anything:
Use Case: [Name]
Trigger: User says "[phrase]" or "[phrase]"
Steps:
1. [First action]
2. [Second action]
Result: [What gets produced]
Then identify which category your skill falls into — this determines which techniques to use. See Skill Categories & Patterns.
Core Principles
- Concise is key - Only add context Claude doesn't already have
- Progressive disclosure - SKILL.md is the overview; details go in
references/ - Write in third person - "This skill processes..." not "I can help you..."
Skill Structure
skill-name/
├── SKILL.md # Main instructions (< 500 lines)
├── scripts/ # Optional: executable code (Python, Bash, etc.)
├── assets/ # Optional: templates, fonts, icons
└── references/ # Detailed docs (loaded on demand)
├── guide.md
└── examples/
YAML Frontmatter
---
name: my-skill-name
description: This skill should be used when the user asks to "do X", "create Y", or mentions Z. Be specific about triggers.
context: fork # Optional: run in isolated context (prevents side effects)
user-invocable: true # Optional: show in slash command menu (default: true)
---
What ships with it
7 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.
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.
- 4d ago First seen · 158 lines · 82 tokens per session scan A 0e014e865f6b
claude-code-skill-development is a skill published in the GitHub repository dwmkerr/claude-toolkit (23 stars, last pushed 10d ago), licensed MIT. It adds 82 tokens to every session and 1,348 once invoked, about $0.0004 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.
Other skills, from other repositories
systematic-debugging
Use when encountering any bug, test failure, or unexpected behavior, before proposing fixes.
brainstorming
You MUST use this before any creative work - creating features, building components, adding functionality, or modifying behavior. Explores user intent, requirements and design before implementation.
auto-perf-optimize
Run agent-driven VS Code performance or memory investigations. Use when asked to launch Code OSS, automate a VS Code scenario, run the Chat memory smoke runner, capture renderer heap snapshots, take workflow screenshots, compare run summaries, or drive a repeatable scenario before heap-snapshot analysis.
chat-perf
Run chat perf benchmarks and memory leak checks against the local dev build or any published VS Code version. Use when investigating chat rendering regressions, validating perf-sensitive changes to chat UI, or checking for memory leaks in the chat response pipeline.
chat-pet-sprite-creation
Use when creating or changing VS Code chat pet sprite art, sprite sheets, state animations, eye treatments, Stable/Insiders variants, or pet transitions under src/vs/workbench/contrib/chat/browser/widget/media/chatPet.
cpu-profile-analysis
Analyze V8/Chrome CPU profiles (.cpuprofile) and DevTools trace files (Trace-.json). Use when: profiling performance, investigating slow functions, comparing code paths, finding bottlenecks, analyzing timeToRequest, understanding call trees from sampling profiler data, analyzing layout/paint/rendering, investigating…