CopilotKit

The core model is a React and Angular SDK that connects your existing frontend to whatever agent backend you're already running — LangChain, CrewAI, or a custom setup — via the AG-UI protocol, a bi-directional event stream the vendor describes as 'the general-purpose connection between a user-facing application and any agentic backend.' Agents render rich UI cards, forms, and widgets inline as they work, not just text responses. Thread and state persistence is handled automatically across sessions. The friction point arrives when your deployment target isn't a web surface: Slack and Teams connections are flagged as early access, which means you're betting on a roadmap, not a shipping feature. Teams with strict approval gates before agent actions can wire those checkpoints in, but the docs describe this as a configuration responsibility rather than a built-in guardrail system.