eval-harness

Evaluate Claude Code sessions with capability and regression evals.

Updated Apr 21, 2026
One-click install
npx skills add https://github.com/choub00/transformer --skill eval-harness-choub00
Or copy as Structured Prompt for Agent▼
Please help me install this Agent Skill.
Skill: eval-harness
Source: https://github.com/choub00/transformer/tree/main/.cursor/skills/eval-harness
Command: npx skills add https://github.com/choub00/transformer --skill eval-harness-choub00

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve?

Formalized evaluation framework for Claude Code sessions enabling reliable, repeatable testing of prompts and models.

Core Features & Use Cases

  • Capability and regression evals
  • Pass@K metrics and model grading
  • End-to-end eval workflow from definition to report

Quick Start

Initialize an eval harness for Claude Code sessions by defining your first capability and regression evals.

Frequently Asked Questions about eval-harness

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I structure regression evals for Claude Code sessions?▼

Run pass@k metrics for Claude Code prompts by using the framework's built-in graders and lightweight automation. It calculates pass@k scores across multiple model attempts to quantify prompt reliability and model capability.

What is eval-driven development for Claude Code?▼

Eval-driven development for Claude Code is a testing methodology where prompt and model changes are validated through formalized evaluation workflows. It uses capability and regression evals to generate repeatable checks and reports before deployment.

How do I set up an evaluation framework for Claude Code prompts?▼

Set up an evaluation framework for Claude Code prompts by initializing structured eval definitions within the .claude/evals directory. Accessible commands then run automated checks and generate reports to test prompts and models reliably.

Can I use eval-harness without external dependencies?▼

Yes, you can use eval-harness without external dependencies because it is a self-contained community framework. It relies on lightweight automation and native Claude Code session commands to execute capability and regression evaluations.

What is the difference between capability and regression evals?▼

Capability evals test new prompt features and model abilities, while regression evals ensure existing functionalities remain intact after changes. Both evaluation types are supported through the structured .claude/evals definitions and pass@k grading system.