Migration

TanStack AI now models approvals, generic pauses, and client-tool execution as AG-UI interrupt descriptors. Native runs end with RUN_FINISHED.outcome.type === 'interrupt', and the continuation is a new run whose parentRunId is the interrupted run.

There is no codemod. Migrate the server lifecycle and client rendering together. Legacy readers stay temporarily for old streams but cannot provide the full native contract. Start from Overview.

API mapping

addToolResult is not removed. It still handles client-tool results and delegates to a matching native item. needsApproval remains the tool-definition switch for approvals.

Single approval

// Before
await addToolApprovalResponse({ id: approval.id, approved: true })

// After
const interrupt = interrupts.find(
  (item) => item.kind === 'tool-approval' && item.toolName === 'transfer',
)
if (interrupt?.kind === 'tool-approval' && interrupt.toolName === 'transfer') {
  interrupt.resolveInterrupt(true)
}

A valid singleton submits automatically. For the full render/resolve component see Tool Approval.

Branch payloads and edits

Legacy boolean approvals couldn't carry typed data. Add approvalSchema and resolve the selected branch with data under payload:

interrupt.resolveInterrupt(true, {
  editedArgs: { amount: 12, recipient: 'Ada' }, // optional, approval-only, full replacement
  payload: { note: 'Reviewed' },
})
interrupt.resolveInterrupt(false, { payload: { reason: 'Policy limit' } })

Rejection never accepts edits; top-level custom fields are invalid. A single approvalSchema (not { approve, reject }) applies to the selected decision; with no schema the boolean shorthand stays valid.

Denial vs cancellation

resolveInterrupt(false, ...) continues the model with an explicit rejected decision. cancel() emits AG-UI status: 'cancelled' and never validates or selects the reject branch. Deprecated addToolApprovalResponse({ approved: false }) maps to denial, not cancellation.

Batches

Native batches are all-or-nothing. Replace approval-ID loops with staged items (the last valid item auto-submits) or one synchronous root callback:

resolveInterrupts((interrupt) => {
  if (interrupt.kind === 'tool-approval') {
    interrupt.resolveInterrupt(true, { payload: { note: 'Batch review' } })
    return
  }
  interrupt.cancel()
})

resolveInterrupts(true|false) is shorthand only for all-approval batches with no payload/edits. Use cancelInterrupts() for payloadless all-items cancel, clearResolution() to drop one draft, retryInterrupts() only when every item is still validly staged and the root error is retryable. See Multiple Interrupts.

Generic responses

Don't derive a static type from a received responseSchema. Parse as unknown, convert with z.fromJSONSchema, then resolve the validated value. Full form example in Generic Interrupts.

Server events

A native server emits, in order: MESSAGES_SNAPSHOT → optional STATE_SNAPSHOT → RUN_FINISHED with a nonempty interrupt outcome. Continuations use a fresh runId, the same threadId, and the interrupted run as parentRunId, with every pending ID present exactly once.

Interrupts run ephemerally: the server reconstructs and validates the expected batch from the submitted history and its current tool definitions, so a stateless route needs no persistence. Because the batch is rebuilt from client-provided input, this mode does not provide authoritative recovery, exactly-once, replay protection, or restart recovery.

resumeInterruptsUnsafe is a low-level escape hatch for submitting validated raw resume entries directly, not the normal target for approval UI.

Legacy limits

Deprecated readers recognize well-formed historical approval-requested and tool-input-available events and convert a fully-covered legacy batch into one cloned-history follow-up. They do not support edited arguments, custom approval payloads, generic responses, payloadless cancellation, or expiry/ schema-hash reconciliation; those fail with legacy-unsupported. Native and legacy items cannot mix in one batch; a failed legacy transport keeps staged decisions and reports legacy-submit-failed.

Checklist

1. Replace native custom-event writers with the interrupt terminal.
2. Render bound interrupts instead of pendingInterrupts.
3. Replace boolean approval helpers with resolveInterrupt + explicit denial/cancellation.
4. Replace approval loops with atomic batch staging or root resolveInterrupts.
5. Keep addToolResult for client-tool results where useful.
6. Test expired items and failed transport before removing legacy support.