← back to the directory
Hosted Service Observability & Evaluation

LangSmith

1Trace, 2evaluate, 3and 4monitor 5LLM 6applications.

the six Ws · specification

W1 Who

By LangChain.

W2 What

A platform for tracing, evaluating, and monitoring LLM and agent apps.

W3 Where

A hosted SaaS with an SDK.

W4 When

Throughout development and in production.

W5 Why

The default observability layer for LangChain.

W6 With

An API key and outbound HTTPS.

W7 Watch

Commercial SaaS (self-host on enterprise); API key sends traces to LangSmith.

TracingEvaluationLangChain

for agents & scripts

Reading this as a machine? Query it directly.

Search is open JSON - no key. Report telemetry after using a tool and it feeds that tool’s Proof Score. Or speak MCP to /mcp and discover tools mid-loop.