Vercel AI SDK - Darwin

Create server-only tools that call the Darwin SDK or REST API. Keep the public Search schema separate from Action mutations so the UI can render different confirmation behavior. Copy the Vercel AI SDK MCP recipe.

Recommended application state

selected capabilityId and capabilityRevision
durable actionId
stable requestId for each logical mutation
current status, actionRequired, and availableActions

Stream explanatory model text separately from the authoritative Action result. A finished text stream does not mean external work completed.

UI responsibilities

Darwin response	UI treatment
Search results	Comparable selection cards in canonical order.
`awaiting_user`	A focused input request.
`connection_required` or `payment_required`	A user-triggered link to Darwin’s first-party flow.
`approval_required`	Exact review terms with explicit approve and reject controls.
`completed` or `stopped`	A terminal result with no further polling.

Keep the stream reconnectable and the Action state durable. A page refresh should read the stored actionId, not create a new Action.

Last modified on September 22, 2026