eval-harness

Implements eval-driven development with capability and regression evals for Claude Code sessions.

Updated Mar 26, 2026
One-click install
npx skills add https://github.com/erwinv2k-TKG/AgentesVSC --skill eval-harness-erwinv2k-tkg
Or copy as Structured Prompt for Agent
Please help me install this Agent Skill.
Skill: eval-harness
Source: https://github.com/erwinv2k-TKG/AgentesVSC/tree/main/packs/everything-claude-code/docs/zh-TW/skills/eval-harness
Command: npx skills add https://github.com/erwinv2k-TKG/AgentesVSC --skill eval-harness-erwinv2k-tkg

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve? AI-assisted coding often lacks a systematic way to verify that changes work as intended and do not break existing behavior. This Skill provides a formal evaluation framework that treats evals as unit tests for AI development, letting you define success criteria before coding and measure reliability with pass@k metrics. ## Core Features & Use Cases - Capability and Regression Evals: Define structured eval templates that test new features and guard existing functionality against regressions. - Multiple Grader Types: Use code-based graders (grep, npm test, build checks), model-based graders for open-ended output scoring, and human review flags for high-risk changes. - Reliability Metrics: Track pass@k and pass^k metrics to measure first-try success rates and consistency across repeated trials. - Use Case: When adding authentication to an app, define evals for signup, login, and session persistence before writing code, then run /eval check add-authentication during implementation and generate a final report showing 5/5 capability evals passing. ## Quick Start Ask the AI to define an eval for a new feature using the eval-harness framework, then implement the code and run the eval check to generate a pass/fail report.

Frequently Asked Questions about eval-harness

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

FAQPage Schema
How do I define evals before writing code with eval-driven development?

Create an eval definition file in .claude/evals/ listing capability evals for new behavior and regression evals for existing functionality. Define success metrics like pass@3 above 90 percent before implementation begins.

What is the difference between pass@k and pass^k metrics?

pass@k measures the probability of at least one success in k attempts, useful for general reliability. pass^k requires all k trials to succeed, a stricter standard used for critical paths where consistency matters.

What grader types can I use to evaluate AI code changes?

Three grader types are supported: code-based graders using deterministic checks like grep or npm test, model-based graders where an AI scores open-ended output on a 1-5 scale, and human review flags for high-risk changes.

Should security checks be fully automated in evals?

No. The framework explicitly recommends human review for security-sensitive changes rather than full automation. Mark these evals with a human review flag including a risk level of LOW, MEDIUM, or HIGH.

Where are eval definitions and results stored in a project?

Evals are stored in a .claude/evals/ directory containing the eval definition markdown file, an execution history log, and a baseline.json file for regression comparison. They should be versioned alongside the code.