add messageHistoryLength to start event

Author: charleslien

backend/src/websockets/websocket-action.ts

@@ -224,6 +224,8 @@ export const callMainPrompt = async (
     chunk: {
       type: 'start',
       agentId: action.sessionState.mainAgentState.agentType ?? undefined,
+      messageHistoryLength:
+        action.sessionState.mainAgentState.messageHistory.length,
     },
   })
 

common/src/types/print-mode.ts

@@ -5,6 +5,7 @@ import { toolResultOutputSchema } from './messages/content-part'
 export const printModeStartSchema = z.object({
   type: z.literal('start'),
   agentId: z.string().optional(),
+  messageHistoryLength: z.number(),
 })
 export type PrintModeStart = z.infer<typeof printModeStartSchema>