lg-eval

Generate and run LangGraph/LangChain agent evaluations in local, LangSmith, or hybrid modes.

4|Updated Apr 15, 2026
One-click install
npx skills add https://github.com/markhazlett/agent-harness --skill lg-eval
Or copy as Structured Prompt for Agent
Please help me install this Agent Skill.
Skill: lg-eval
Source: https://github.com/markhazlett/agent-harness/tree/main/.claude/skills/lg-eval
Command: npx skills add https://github.com/markhazlett/agent-harness --skill lg-eval

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve?

Automates the setup and execution of robust evaluations for LangGraph/LangChain agents, enabling deterministic tests, experiment tracking, and dashboard insights across local and LangSmith-backed workflows.

Core Features & Use Cases

  • Supports Local-only, LangSmith-backed, and Hybrid evaluation modes with dataset scaffolding, evaluators, and test harness integration.
  • Generates reusable evaluators for trajectory, final-answer correctness, smoke checks, and optional structured-output checks; can upload datasets to LangSmith for dashboards.
  • Use Case: A team adds evals to verify a new agent's behavior across tool usage and responses, then runs recordings in CI and reviews results in LangSmith dashboards.

Quick Start

Configure your agent and run the evaluator using the chosen mode (local-only, LangSmith-backed, or hybrid).

Frequently Asked Questions about lg-eval

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

FAQPage Schema
How do I set up automated evaluations for LangGraph agents?

Automated evaluations for LangGraph agents are set up by detecting the target agent, reading its state shape and tool list, and generating dataset scaffolding, evaluators, and test harness files to run the evaluation workflow.

Can I run LangChain agent testing without a LangSmith API key?

LangChain agent testing can run without a LangSmith API key by downgrading to local-only mode, which verifies dependencies and executes evaluations locally without requiring LangSmith-backed dashboards.

What types of evaluators are generated for LangChain agent testing?

Evaluators generated for LangChain agent testing include trajectory checks, final-answer correctness, smoke checks, and optional structured-output checks, which can be reused across local and hybrid evaluation modes.

Does LangSmith integration support experiment tracking for agent evaluations?

LangSmith integration supports experiment tracking for agent evaluations by uploading datasets to LangSmith, enabling dashboard insights, and running recordings in CI across hybrid workflows.

What is the best way to test agent behavior across tool usage and responses?

The best way to test agent behavior across tool usage and responses is to generate reusable evaluators for trajectory and final-answer correctness, wire them into a test harness, and run the evaluation workflow in local or hybrid mode.

Do I need to define a dataset before running LangGraph agent evals?

LangGraph agent evals do not require a pre-existing dataset, as the workflow generates dataset scaffolding tailored to the agent's state shape and tool list before running the evaluation.