ChatMiddlewarePhase | TanStack AI Docs

type ChatMiddlewarePhase = 
  | "init"
  | "beforeModel"
  | "afterModel"
  | "modelStream"
  | "beforeTools"
  | "afterTools"
  | "structuredOutput";

Defined in: packages/ai/src/activities/chat/middleware/types.ts:96

Phase of the chat middleware lifecycle.

'init': Initial config transform before the chat engine starts
'beforeModel': Before each adapter chatStream call (per agent iteration)
'afterModel': After each adapter chatStream call (per agent iteration)
'modelStream': During model streaming
'beforeTools': Before tool execution phase
'afterTools': After tool execution phase
'structuredOutput': During the final structured-output adapter call (set for chunks from adapter.structuredOutputStream or the synthesized fallback)