skill-dev

skill-dev is a skill for Claude Code from andisab/swe-marketplace. It costs 86 tokens per session (5,516 once invoked), scanned A, original, MIT.

A guide for creating Claude Code skills, which are reusable instructions and resources that Claude can activate automatically when a task matches them.

In plain words
What is it for?
Use it to design skill definitions, distinguish skills from agents, organize supporting files, and follow Anthropic's documented conventions.
Why use it?
It helps avoid unfocused skill descriptions and incorrect folder structures, making new skills easier for Claude to discover and use.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter. Also seen: reads .claude/ paths; mentions subagents; mentions Claude Code.

Part of the context-engineering plugin — 7 skills, 1 agent shipped together

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/andisab/swe-marketplace/skill-dev
Any agent
npx skills add andisab/swe-marketplace --skill skill-dev
Clone the repo
git clone --depth 1 https://github.com/andisab/swe-marketplace

Made for: Claude Code.

Or install context-engineering, the plugin that ships this one along with the rest of its 7 skills, 1 agent.

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-dev

README.md
[![agentmods](https://agentmods.dev/badge/skills/andisab/swe-marketplace/skill-dev.svg)](https://agentmods.dev/skills/andisab/swe-marketplace/skill-dev)
Your own site
<a href="https://agentmods.dev/skills/andisab/swe-marketplace/skill-dev"><img src="https://agentmods.dev/badge/skills/andisab/swe-marketplace/skill-dev.svg" alt="Measured on agentmods" height="20"></a>
Per session 86 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 5,516 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 5.1 $0.00086 $0.05516
Opus 5 $0.00043 $0.02758
Sonnet 5 $0.00017 $0.01103
Haiku 4.5 $0.00009 $0.00552

Measured 6d ago against content hash 8b1be5978a25, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

skill-dev 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 6d 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.

plugins/context-engineering/skills/skill-dev/SKILL.md · 819 lines

How it starts

The opening of the file, as written. The whole thing — 819 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Skill Dev Skill

This skill helps create production-ready Claude Code skills following Anthropic's official specifications and best practices.

Skills vs Agents: Key Differences

Aspect Skills Sub-agents
Invocation Model-invoked (automatic) User-invoked (explicit) or Task tool
Scope Single capability Multiple capabilities
File Directory with SKILL.md Single .md file
Supporting files Can include templates, scripts System prompt only
Discovery Description matching Description + explicit invocation
Use case Reusable patterns, tools, workflows Specialized AI assistants

When to use Skills: Create autonomous capabilities that Claude should invoke automatically when context matches (e.g., PDF processing, form filling, specific workflows)

When to use Agents: Create specialized AI assistants for complex domains requiring multi-step reasoning (e.g., database expert, security auditor)

Use Case Categories

Anthropic identifies three common skill categories:

Category Purpose Example
Document & Asset Creation Produce tangible outputs (reports, documents, designs, code) A frontend-design skill that creates production-grade UI components
Workflow Automation Orchestrate multi-step processes with validation gates A skill-creator skill that walks users through use case definition, frontmatter, and validation
MCP Enhancement Add knowledge and best practices on top of MCP tool access A sentry-code-review skill that uses Sentry's MCP to analyze and fix bugs in PRs

The kitchen analogy: MCP provides the professional kitchen (tools, ingredients, equipment). Skills provide the recipes (step-by-step instructions on how to create something valuable). Together, they enable users to accomplish complex tasks without figuring out every step themselves. See patterns/skill-mcp-integration.md for in-depth MCP integration guidance.

Read the full file on GitHub · 819 lines

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. 6d ago First seen · 819 lines · 86 tokens per session scan A 8b1be5978a25

Subscribe to this mod's changes

skill-dev is a skill published in the GitHub repository andisab/swe-marketplace (21 stars, last pushed 18d ago), licensed MIT. It adds 86 tokens to every session and 5,516 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.