fix: correct GPT-5 response ID persistence and usage

- Renamed metadata field from 'previous_response_id' to 'response_id' for clarity
- Fixed logic to correctly use the response_id from the previous message as previous_response_id for the next request
- This resolves the 'Previous response with id not found' errors that occurred after multiple turns in the same session

Author: hannesrudolph

src/core/task/Task.ts

@@ -1751,7 +1751,7 @@ export class Task extends EventEmitter<TaskEvents> implements TaskLike {
 				presentAssistantMessage(this)
 			}
 
-			// Persist GPT‑5 per-turn metadata (previous_response_id, instructions)
+			// Persist GPT‑5 per-turn metadata (response_id, instructions)
 			try {
 				const modelId = this.api.getModel().id
 				if (modelId && modelId.startsWith("gpt-5")) {
@@ -1765,7 +1765,7 @@ export class Task extends EventEmitter<TaskEvents> implements TaskLike {
 						msg.metadata = msg.metadata ?? {}
 						msg.metadata.gpt5 = {
 							...(msg.metadata.gpt5 ?? {}),
-							previous_response_id: lastResponseId,
+							response_id: lastResponseId, // This is the response ID generated by THIS turn
 							instructions: this.lastUsedInstructions,
 							reasoning_summary: (reasoningMessage ?? "").trim() || undefined,
 						}
@@ -2074,16 +2074,16 @@ export class Task extends EventEmitter<TaskEvents> implements TaskLike {
 		try {
 			const modelId = this.api.getModel().id
 			if (modelId && modelId.startsWith("gpt-5") && !this.skipPrevResponseIdOnce) {
+				// Find the last assistant message that has a response_id stored
 				const idx = findLastIndex(
 					this.clineMessages,
-					(m) =>
-						m.type === "say" &&
-						(m as any).say === "text" &&
-						(m as any).metadata?.gpt5?.previous_response_id,
+					(m) => m.type === "say" && (m as any).say === "text" && (m as any).metadata?.gpt5?.response_id,
 				)
 				if (idx !== -1) {
-					previousResponseId = ((this.clineMessages[idx] as any).metadata.gpt5.previous_response_id ||
-						undefined) as string | undefined
+					// Use the response_id from the last assistant message as the previous_response_id for this request
+					previousResponseId = ((this.clineMessages[idx] as any).metadata.gpt5.response_id || undefined) as
+						| string
+						| undefined
 				}
 			}
 		} catch {