Use when creating or improving Claude Code agents. Expert guidance on agent file structure, frontmatter, persona definition, tool access, model selection, and validation against schema.
SkillScore91Maintained
Automatic
◆AI Engineer pack
Last verified 8/14/2026
What it changes
Passed 20 of 22 test cases with the skill, and 13 of 22 without it.
Without skill59%
With skill91%
Checks it passed that the model alone missed
sets model to opus
sets model to haiku
sets model to inherit
and 6 more in the full report
8 fixed12 passed either way1 still failing1 broke
Pass-rate lift
+32 pp
Tokens
+223%
Agent turns
0%
Response time
-40%
Model gemini-3.6-flashMeasured 8/14/2026v120 of 22 cases passed with skill
Tokens, turns and time describe resource use, not a dollar price.
See it in action
One of 8 test cases the skill fixed. Same model, same prompt, with and without the skill.
1 of 8
Prompt
We need a lightweight, fast agent that performs simple syntax checking and lint error summaries with minimum latency and lower cost. Which model frontmatter value is appropriate?
What was checked, without and with the skill
Checked
Without skill
With skill
sets model to haiku
Missed
Passed
case-12 · gemini-3.6-flash · 8/14/2026 · answers are capped and redacted
What's inside
The instructions your model reads when the skill loads.
SKILL.md661 linessingle file
Creating Claude Code Agents - Expert Skill
Use this skill when creating or improving Claude Code agents. Provides comprehensive guidance on agent structure, schema validation, and best practices for building long-running AI assistants.
When to Use This Skill
Activate this skill when:
User asks to create a new Claude Code agent
User wants to improve an existing agent
User needs help with agent frontmatter or structure
User is troubleshooting agent validation issues
User wants to understand agent format requirements
User asks about agent vs skill vs slash command differences
Quick Reference
Agent File Structure
---
name: agent-name
description: When and why to use this agent
allowed-tools: Read, Write, Bash
model: sonnet
agentType: agent
---
# 🔍 Agent Display Name
You are [persona definition - describe the agent's role and expertise].
## Instructions
[Clear, actionable guidance on what the agent does]
## Process
[Step-by-step workflow the agent follows]
Use when seeing WebSocket errors like "Invalid frame header", "RSV1 must be clear", or "WS_ERR_UNEXPECTED_RSV_1" - covers multiple WebSocketServer conflicts, compression issues, and raw frame debugging techniques