---
title: "Agent Skill"
description: "Teach AI agents how to write evals"
---

# Agent Skill

EZVals includes a skill that teaches AI coding agents how to write and analyze evaluations.

## What's a Skill?

Skills are markdown files that provide context and instructions to AI coding agents like Claude Code, Cursor, and others. When you ask your agent to help with evals, it can reference the skill to understand:

- EZVals API and patterns
- Best practices for eval design
- Grading strategies (code vs model vs human)
- Patterns for different agent types

## Installation

### From Package (Version-Matched)

Install the skill that matches your installed EZVals version:

```bash
pip install ezvals
ezvals skills add --claude
```

This installs to your current project directory.

### Global Installation

Install globally for all projects:

```bash
ezvals skills add --global --claude
```

### Target Flags

`ezvals skills add` requires at least one explicit target flag.

- `--agents` installs canonical source to `.agents/skills/evals/`
- `--claude`, `--codex`, `--cursor`, `--windsurf`, `--kiro`, `--roo` install/link those agent directories
- You can combine flags, like `ezvals skills add --claude --codex`
- If `--agents` is included with other targets, `.agents` is canonical and selected agent targets link to it

### From Marketplace (Latest)

Install the latest version from the skills marketplace:

```bash
npx skills add camronh/evals-skill
```

## Usage

After installation, invoke the skill in your AI coding agent:

```
/evals
```

Or just ask about evals - agents will automatically detect and use the skill based on context.

## What's Included

The skill provides comprehensive guidance across multiple reference files:

| File | Purpose |
|------|---------|
| **SKILL.md** | Overview and navigation hub |
| **EZVALS_REFERENCE.md** | Complete API reference for @eval, EvalContext, @parametrize |
| **BEST_PRACTICES.md** | Eval design principles from Anthropic's research |
| **GRADERS.md** | Choosing between code, model, and human graders |
| **AGENT_EVALS.md** | Patterns for coding, conversational, research agents |
| **ROADMAP.md** | Zero-to-one guide for building evals |

## Example Prompts

Try these prompts with your AI coding agent:

### Getting Started
- "Help me write my first eval for my customer support agent"
- "What's the best way to evaluate my RAG pipeline?"
- "Set up an eval suite for my coding assistant"

### Writing Evals
- "Create an eval that tests my agent's ability to handle refund requests"
- "Write a parametrized eval for testing sentiment analysis across edge cases"
- "How do I test multi-turn conversations?"

### Improving Evals
- "My eval is flaky - help me make it more deterministic"
- "Should I use code-based or model-based grading for this eval?"
- "Review my evals and suggest improvements"

### Analysis
- "Analyze my eval results and suggest improvements"
- "Help me understand why my agent is failing this eval"
- "What patterns do you see in these failures?"

## Managing the Skill

### Check Installation

```bash
ezvals skills doctor
```

Shows installation status, version, and symlink health.

### Remove Skill

```bash
ezvals skills remove
```

### Reinstall

```bash
ezvals skills add --claude
```

Overwrites existing installation with fresh files.

## How It Works

The skill is installed only to the selected target directories:

```
.claude/skills/evals/     # Selected with --claude
.cursor/skills/evals/     # Selected with --cursor
.codex/skills/evals/      # Selected with --codex
...
```

If `--agents` is selected, `.agents/skills/evals/` is the canonical source and other selected targets symlink to it.

## Keeping Updated

When you upgrade EZVals, run `ezvals skills add --claude` again (or your chosen target flags) to get the latest skill content:

```bash
pip install --upgrade ezvals
ezvals skills add --claude
```
