Client-orchestrated chat widget: fetches host-side aiActions + .well-known/mcp.json manifests, dispatches tool_calls locally or directly to MCP endpoints, and consumes the llm_meta_server's SSE-streamed single_llm_calls API. Ships as a custom element in one self-contained ES module — served by this gem's helper for Rails hosts, and published to npm as @aibranch/llm-meta-widget for hosts that are not Rails. No Devise, no DB migrations, no chat_manager.