{"id":"langsmith-api","name":"LangSmith","homepage":"https://smith.langchain.com","repo_url":"https://github.com/langchain-ai/langsmith-sdk","category":"ai-ml","subcategories":["llm-observability","agent-evaluation","ai-debugging"],"tags":["langsmith","langchain","llm-observability","tracing","evaluation","ai-agents","debugging"],"what_it_does":"LLM observability and evaluation platform from LangChain that traces, monitors, and evaluates LLM application runs including agent chains, with a REST API for programmatic access to traces and evaluation datasets.","use_cases":["Tracing agent execution steps to debug multi-turn LLM workflows","Running automated evaluations against golden datasets to measure LLM output quality","Querying run history to identify patterns in failures and latency spikes","Creating and managing evaluation datasets for regression testing of prompts","Monitoring production LLM applications for cost, latency, and quality metrics"],"not_for":["General application performance monitoring (use Datadog or New Relic for non-LLM tracing)","Teams not using LangChain ecosystem (integration is deeper for LangChain users)","Real-time alerting on latency or errors (limited alerting capabilities)","Open-source teams requiring fully self-hosted observability with no SaaS dependency"],"best_when":"You're building LangChain-based agents or any LLM application and want traces, evals, and debugging without building custom observability infrastructure.","avoid_when":"You're using a different observability platform already integrated with your LLM stack, or you need general APM capabilities beyond LLM-specific tracing.","alternatives":["honeycomb-api","wandb-api","datadog-api","sentry-api"],"af_score":76.2,"security_score":null,"reliability_score":null,"package_type":"mcp_server","discovery_source":["github"],"priority":"low","status":"evaluated","version_evaluated":"current","last_evaluated":"2026-03-01T09:50:05.771194+00:00","performance":{"latency_p50_ms":80,"latency_p99_ms":300,"uptime_sla_percent":99.9,"rate_limits":"API rate limits not prominently documented; depends on plan","data_source":"llm_estimated","measured_on":null}}