LangSmith

LangSmith is a framework-agnostic platform for building, debugging, and deploying AI agents and LLM applications. Trace requests, evaluate outputs, test prompts, and manage deployments all in one place at smith.langchain.com.

When to use

Use LangSmith when you need to:

• Trace and debug LLM calls, agent steps, retrieval, and tool use
• Evaluate LLM outputs with automated or human-in-the-loop scoring
• Engineer prompts with a visual playground and version control
• Deploy agents to production with the LangGraph-based agent server
• Monitor production systems with dashboards, alerts, and cost tracking

When NOT to use

• To build agent logic or LLM pipelines, use LangChain, LangGraph, or Deep Agents instead
• LangSmith is the platform layer that complements these frameworks

Quick setup