AgentServerOptions

API key for authentication.

• If a string is provided, that key will be used
• If undefined (default), the key will be auto-loaded from environment variables (LANGGRAPH_API_KEY, LANGSMITH_API_KEY, or LANGCHAIN_API_KEY)
• If null, no API key will be set (skips auto-loading)

Options forwarded to the internal AsyncCaller, such as retry, concurrency, or custom fetch behavior.

LangGraph SDK client used to send requests and receive responses.

Headers applied to every request.

The configured API key, when present, is added as the x-api-key header after these defaults are initialized.

Optional fetch override, forwarded to the SSE transport. Useful for auth proxies, Next.js route handlers, or tests with injected mocks. Ignored when webSocketFactory is also supplied.

Initial values to display immediately when loading a thread. Useful for displaying cached thread data while official history loads. These values will be replaced when official thread data is fetched.

Note: UI components from initialValues will render immediately if they're predefined in LoadExternalComponent's components prop, providing instant cached UI display without server fetches.

Specify the key within the state that contains messages. Defaults to "messages".

Convenience callback fired when a run's active streaming phase ends. runId may be omitted for re-attached in-flight runs because no local dispatch response was observed.

Callback that is called when a new stream is created.

Callback that is called when the thread ID is updated (ie when a new thread is created).

Optimistic UI for submit(). When enabled (the default), the input passed to submit() is reflected in values / messages immediately — before the server responds — then reconciled against the authoritative server state as it streams in:

• Messages in the input are appended right away. Any message without an id is assigned a stable client id (sent to the server, which add_messages preserves) so the server echo reconciles by id instead of duplicating. Per-message progress is exposed via useMessageMetadata(stream, id).optimisticStatus ("pending" → "sent", or "failed" if the run errors before the message is echoed; failed optimistic messages are kept for retry UIs and dropped on the next hydrate()).
• Other input keys are shallow-merged into values and converge to server truth on the first values event (or are rolled back if the run fails before any echo).

Set to false to dispatch input verbatim with no client-side echo or id minting (server-authoritative only) — useful for non-chat state graphs or deterministic SSR/tests.

Thread ID this transport currently targets.

How this thread talks to the agent server. Accepts either a built-in transport string or a custom AgentServerAdapter:

• "sse": HTTP commands + one SSE event stream per subscription.
• "websocket": single bidirectional WebSocket.
• an AgentServerAdapter: custom transport that replaces the built-in factories entirely. fetch / webSocketFactory are ignored in this mode.

Defaults to the client-level streamProtocol ("v2-websocket" → "websocket", otherwise "sse").

Optional WebSocket factory. Supplying it flips the adapter into WebSocket mode — SSE is bypassed entirely.