Copilots

assistant-ui Copilots

Always consult assistant-ui.com/llms.txt for the latest API.

Copilots ground an assistant in your running app: steer it with instructions, feed it lazy app state, let it read and drive rendered components, give it two way state through interactables, and share model context across an iframe boundary.

References

• ./references/instructions.md -- useAssistantInstructions
• ./references/model-context.md -- useAssistantContext, imperative modelContext().register, ModelContextRegistry
• ./references/visible.md -- makeAssistantVisible
• ./references/interactables.md -- app-scoped and thread-scoped interactables, versions, persistence, partial updates
• ./references/assistant-frame.md -- AssistantFrameProvider and useAssistantFrameHost

Orientation

All APIs ship from @assistant-ui/react and run inside AssistantRuntimeProvider. Pick the smallest tool for the job:

What do you need the assistant to know or do?
├─ Steer behavior with a system prompt → useAssistantInstructions("...")
├─ Feed read-only app state (page, selection, cart) → useAssistantContext({ getContext })
├─ Let it read / click / edit a rendered component → makeAssistantVisible(Component, { clickable, editable })
├─ Read AND write persistent component state via tools
│    ├─ Mounted by you, anywhere in the app → unstable_useInteractable(name, config)
│    └─ Created by the model, inline in the thread → unstable_interactableTool(config) inside defineToolkit
├─ Register instructions + tools together imperatively → aui.modelContext.register({ getModelContext })
└─ Share tools/instructions with a parent window from an embedded iframe → AssistantFrameProvider + useAssistantFrameHost

Instructions and context are the lightweight starting point. Reach for makeAssistantVisible when the assistant needs to perceive or drive existing DOM, and for interactables when it needs structured two-way state it can mutate through auto-generated update_{name} tools.

Interactables have two generations. The current one is the unstable_ family (unstable_Interactables(), unstable_useInteractable, unstable_interactableTool); the prefix flags it as subject to change, not as unsupported. The legacy family (Interactables(), useAssistantInteractable, useInteractableState) is deprecated as of 2026-06-14 and scheduled for removal on or after 2026-09-14. The two scopes are mutually exclusive: mount only one interactables API in one AuiConfig.

import { useAssistantInstructions, useAssistantContext } from "@assistant-ui/react";

function CheckoutCopilot() {
  useAssistantInstructions("You help users complete checkout. Be concise.");
  useAssistantContext({ getContext: () => `Current page: ${window.location.href}` });
  return null;
}

getContext is evaluated fresh each time the model context is read, so it always reflects current state. Register imperatively when instructions and tools need to ship from the same provider:

import { useAui } from "@assistant-ui/react";
import { useEffect } from "react";

function SearchCopilot() {
  const aui = useAui();
  useEffect(() => {
    return aui.modelContext.register({
      getModelContext: () => ({
        system: "You are a helpful search assistant.",
        tools: { search: mySearchTool },
      }),
    });
  }, [aui]);
  return null;
}

register returns an unsubscribe function; returning it from useEffect cleans up the provider on unmount. Multiple providers compose: system strings concatenate and tools maps merge.

Interactables scope

Mount the scope once through config. App-scoped and thread-scoped interactables both need it; thread-scoped ones also need their toolkit registered.

import { AuiConfig, AssistantRuntimeProvider, unstable_Interactables } from "@assistant-ui/react";
import { useChatRuntime } from "@assistant-ui/ai-sdk";

function Providers({ children }: { children: React.ReactNode }) {
  const runtime = useChatRuntime();
  const config = AuiConfig({ unstable_interactables: unstable_Interactables() });

  return (
    <AssistantRuntimeProvider runtime={runtime} config={config}>
      {children}
    </AssistantRuntimeProvider>
  );
}

unstable_useInteractable(name, config) then registers an instance and returns [state, { id, setState, isPending, error, flush }]; the framework generates an update_{name} tool from a partial version of your stateSchema. See interactables.md for the thread-scoped form, versions, persistence, and how partial updates merge.

Common Gotchas

Assistant ignores instructions or context

• The hook or register call must run inside AssistantRuntimeProvider.
• For aui.modelContext.register, call it in useEffect and return the result so it unsubscribes; registering in render leaks providers.

Context is stale

• Use the getContext callback form, not a captured value. It is re-read at send time, so closures over fresh state work; a precomputed string will not update.

makeAssistantVisible does nothing

• Without options the component is read-only (exposes its outerHTML). Pass { clickable: true } to allow clicks and { editable: true } for <input> / <textarea> editing. Nested visible components expose only the outermost.

Interactable resets its state on every render

• Define stateSchema and initialState outside the component (or memoize them). A new schema identity on every render re-registers the interactable and wipes its state.

Two interactables scopes registered at once

• unstable_Interactables() and the legacy Interactables() are mutually exclusive. Keep exactly one in AuiConfig; new code uses unstable_Interactables().

Partial updates don't land the way you expect

• Plain fields merge shallowly: the model sends only what changed, and a nested object it sends replaces that field rather than deep-merging into it.
• Array fields whose items carry an id take operations (add / update / remove / clear) instead of a replacement array.

Frame host never receives tools or instructions

• Both sides validate message origin. The iframe's AssistantFrameProvider.addModelContextProvider(registry, targetOrigin) and the parent's useAssistantFrameHost({ targetOrigin }) must name the same explicit origin for a cross-origin embed; omitting targetOrigin on either side defaults to that window's own origin.

Related Skills

• tools -- toolkits (defineToolkit), backend and frontend tool definitions, and custom tool-call UI.
• runtime -- runtime creation, AssistantRuntimeProvider, and reading or mutating thread state (useAui, useAuiState, useAuiEvent).