LangWatch

LangWatch is the open-core platform to test, simulate, and monitor AI agents end-to-end. Unlike tools that grade single LLM outputs, LangWatch is built for agent complexity; multi-turn, multi-step, multi-agent systems where failure hides in the interactions. Killer feature: Scenario, agent simulation before production. Open-source framework for simulating full multi-turn agent conversations, including adversarial and edge-case paths, so you catch broken behavior before your users do. This is the wedge: almost every competitor evaluates outputs; LangWatch tests agents the way software teams test software. Voice agents included