“Testing”

Open-source agent harness from LangChain for building agents with code, with LangSmith for testing and monitoring.

TypeScript toolkit for agents with Zod-typed tools, graph and multi-agent workflows, and Node.js or browser runtimes.

TypeScript agent framework with persistent cognitive memory, multi-agent orchestration and one dispatch interface across 13 LLM providers.

XState library where agent logic is a state machine, so a model can only pick events the machine allows.