LangSmith

LangSmith is a developer platform built by LangChain Inc. for debugging, testing, evaluating, and monitoring LLM-powered applications and agent workflows. It provides end-to-end tracing of agent executions—showing every LLM call, tool invocation, and decision point in a multi-step workflow—alongside evaluation tools for measuring agent performance against defined benchmarks.

LangSmith addresses a critical pain point in production agent systems: understanding why an agent succeeded or failed across complex, multi-step workflows. Its tracing capabilities let developers inspect the full chain of reasoning, identify latency bottlenecks, and catch failure modes before they reach users. The evaluation framework enables systematic testing of agent behavior across diverse scenarios.

In the Seven Layers of the Agentic Economy, LangSmith operates at Layer 2 (Creation & Orchestration) in the Observability & Eval subsection—providing the monitoring and evaluation infrastructure that production agent systems require.