AgentsKit

AgentsKit is a lightweight JavaScript toolkit for constructing AI agents with a 10 KB core and modular architecture. It provides runtime, tools, memory, RAG, and UI bindings in a single foundation, supporting 25 model adapters across 222 providers and 50 built-in integrations including OpenAI, Anthropic, Stripe, and Notion. Users can swap components—changing models from OpenAI to Claude or UIs from React to terminal—without rewriting code.

Designed for developers building agent applications, AgentsKit eliminates the need to glue together multiple libraries. The framework uses six formal contracts to make every adapter, tool, memory backend, and runtime substitutable. It includes a CLI for scaffolding agents, support for multi-agent systems and ReAct planning, and integrations with observability tools like LangSmith.