Agent layer for AI Elements (on top of ai-elements-chat): streaming protocol backends (AI SDK, AG-UI, OpenAI, Anthropic, Gemini, Ollama), on-device tools and OAuth sign-in. No Compose.

In-app agent harness: a model plus composable capabilities (tools, skills, MCP, sub-agents) as one ChatBackend, mirroring Pydantic AI Harness.

Agent2Agent (A2A 1.0) for AI Elements: remote agents as chat providers and sub-agents, on the official A2A Java SDK.

Agent Client Protocol (ACP) for AI Elements: coding agents such as Claude Code, Codex or Gemini CLI as chat providers, on the official ACP Kotlin SDK.

JetBrains Koog agents for AI Elements: a Koog agent run as a ChatBackend, with AI Elements tools and capabilities as Koog tools.

An MCP Apps host (io.modelcontextprotocol/ui, 2026-01-26) for AI Elements: interactive ui:// views of MCP tools in a sandboxed WebView with CSP, bridged to the MCP client and rendered in the chat.