better-skill-builder

Build Agent Skills for Claude Code, Codex, Amp, and OpenCode.

A skill that teaches you, an AI agent, how to help users build skills. Meta, but useful.

Claude Code users: The built-in claude-code-guide agent intercepts "Agent Skill" queries. Say "use my skills" or "use better-skill-builder" to use this instead.

Why "Better"?

Anthropic's skill-creator is comprehensive but theoretical. This skill is battle-tested.

The irony: skill-creator preaches "context window is a public good" and "keep SKILL.md under 500 lines" but inlines ~3000 words of spec content. We link to agentskills.io instead. AI agents know how to fetch URLs. And when the spec updates, our skill stays current automatically.

This skill teaches from real code, not theory.

Official docs: agentskills.io

Production Skills

GNO - Local Knowledge Engine

Your local second brain. Index notes, code, PDFs, Office docs. Hybrid search (BM25 + vector + reranking) and AI answers, 100% offline.

bun install -g @gmickel/gno
gno init ~/notes --name notes
gno query "auth best practices"
gno ask "summarize the API" --answer

Skill install:

gno skill install --target claude --scope user
gno skill install --target codex

Also: MCP server for Claude Desktop, Cursor, Zed, and 8 more targets.

gno.sh | GitHub

sheets-cli - Google Sheets Primitives

Composable CLI for Google Sheets. Read tables, append rows, update by key, batch ops. JSON in, JSON out.

sheets-cli read table --sheet "Projects" --limit 10
sheets-cli update key --sheet "Projects" --key-col "Name" --key "Acme" --set '{"Status":"Done"}'

Skill install:

sheets-cli install-skill --global   # Claude Code
sheets-cli install-skill --codex    # Codex

GitHub

raindrop-skill - Bookmark Manager

Manage Raindrop.io bookmarks, collections, tags, highlights via API.

git clone https://github.com/gmickel/raindrop-skill ~/.claude/skills/raindrop
export RAINDROP_TOKEN="your_token"

Uses a helper script for curl calls. Simple pattern for wrapping any REST API.

GitHub

outlookctl - Outlook Automation

Automate Classic Outlook on Windows via COM. Email and calendar with safety-first design.

• Draft-first workflow (never auto-send)
• Explicit confirmation required
• Full calendar support

uv run python tools/install_skill.py --personal

GitHub

Flow - Plan-First Workflow

Plugin with 7 skills, 5 commands, 6 agents. Plan before you code, drift never.

/plugin marketplace add https://github.com/gmickel/gmickel-claude-marketplace
/plugin install flow
/flow:plan Add OAuth login
/flow:work plans/add-oauth-login.md

GitHub

Building Your Own Skills

Quick Start

# Minimal structure
my-skill/
  SKILL.md           # Required

# With references
my-skill/
  SKILL.md           # Main (<500 lines)
  references/
    cli-reference.md
    examples.md

SKILL.md Format

---
name: my-skill
description: >
  What it does. Include trigger phrases so AI
  knows when to activate this skill.
---

# Content here

What You'll Learn

Key Principles

1. Progressive disclosure - Main file scannable, details in references
2. Trigger-aware descriptions - Help AI know WHEN to use the skill
3. Safety patterns - Draft-first, dry-run, explicit confirmation
4. Environment variables - Standard pattern for auth tokens

Distribution Options

Installation Paths

Install This Skill

git clone https://github.com/gmickel/better-skill-builder ~/.claude/skills/better-skill-builder

Then ask: "How do I create a SKILL.md? Use my skills."

Resources

• agentskills.io/specification - Official spec
• agentskills.io/integrate-skills - Client integration
• anthropics/skills - Official examples

License

MIT