LangSmith

LangSmith is a developer platform designed specifically for the challenges of building and maintaining AI applications. It records the full trace of every model call — inputs, outputs, intermediate steps, latency, and costs — making it possible to debug failures, compare prompts, and evaluate behavior in a structured way. It integrates natively with LangChain but works with other frameworks as well. For behavior architects and AI engineers, LangSmith reduces the friction of getting visibility into model behavior during development: instead of manually logging and analyzing outputs, teams get structured traces they can filter, annotate, and run evaluations against directly in the tool.