Separate live text and tool stream parts

frontend/app/app/api/chat/route.ts

@@ -53,6 +53,8 @@ type ClawStreamItem =
 type StreamState = {
 	textStarted: boolean;
 	textStreamed: boolean;
+	textPartIndex: number;
+	activeTextId?: string;
 	reasoningEnded: boolean;
 	phase: "waiting" | "queued" | "running" | "done";
 	runId?: string;
@@ -112,6 +114,7 @@ export async function POST(req: Request) {
 			const streamState: StreamState = {
 				textStarted: false,
 				textStreamed: false,
+				textPartIndex: 0,
 				reasoningEnded: false,
 				phase: "waiting",
 				announcedToolCallKeys: new Set<string>(),
@@ -151,13 +154,9 @@ export async function POST(req: Request) {
 				}
 				writeToolTrace(writer, payload.transcript, streamState);
 				if (!streamState.textStreamed) {
-					writer.write({ type: "text-start", id: "text-1" });
+					writeTextDelta(writer, text, streamState);
-					writer.write({ type: "text-delta", id: "text-1", delta: text });
-					writer.write({ type: "text-end", id: "text-1" });
-				} else if (streamState.textStarted) {
-					writer.write({ type: "text-end", id: "text-1" });
-					streamState.textStarted = false;
 				}
+				endTextPart(writer, streamState);
 				writer.write({ type: "finish-step" });
 				writer.write({
 					type: "finish",
@@ -178,9 +177,9 @@ export async function POST(req: Request) {
 							? err.message
 							: "请求失败。";
 				writer.write({ type: "reasoning-end", id: "reasoning-1" });
-				writer.write({ type: "text-start", id: "text-1" });
+				endTextPart(writer, streamState);
-				writer.write({ type: "text-delta", id: "text-1", delta: text });
+				writeTextDelta(writer, text, streamState);
-				writer.write({ type: "text-end", id: "text-1" });
+				endTextPart(writer, streamState);
 				writer.write({ type: "finish-step" });
 				writer.write({
 					type: "finish",
@@ -209,6 +208,45 @@ function formatDuration(ms: number) {
 	return seconds > 0 ? `${minutes}min${seconds}s` : `${minutes}min`;
 }
 
+function startTextPart(
+	writer: UIMessageStreamWriter<UIMessage>,
+	streamState: StreamState,
+) {
+	if (streamState.textStarted && streamState.activeTextId) {
+		return streamState.activeTextId;
+	}
+	streamState.textPartIndex += 1;
+	const id = `text-${streamState.textPartIndex}`;
+	streamState.activeTextId = id;
+	streamState.textStarted = true;
+	writer.write({ type: "text-start", id });
+	return id;
+}
+
+function writeTextDelta(
+	writer: UIMessageStreamWriter<UIMessage>,
+	delta: string,
+	streamState?: StreamState,
+) {
+	if (!streamState) {
+		writer.write({ type: "text-delta", id: "text-1", delta });
+		return;
+	}
+	const id = startTextPart(writer, streamState);
+	writer.write({ type: "text-delta", id, delta });
+	streamState.textStreamed = true;
+}
+
+function endTextPart(
+	writer: UIMessageStreamWriter<UIMessage>,
+	streamState?: StreamState,
+) {
+	if (!streamState?.textStarted || !streamState.activeTextId) return;
+	writer.write({ type: "text-end", id: streamState.activeTextId });
+	streamState.textStarted = false;
+	streamState.activeTextId = undefined;
+}
+
 function writeToolTrace(
 	writer: UIMessageStreamWriter<UIMessage>,
 	transcript?: ClawTranscriptEntry[],
@@ -232,6 +270,7 @@ function writeToolTrace(
 			if (!toolCallId || !toolName) continue;
 			if (streamState?.streamedToolCallIds.has(toolCallId)) continue;
 
+			endTextPart(writer, streamState);
 			writer.write({
 				type: "tool-input-available",
 				toolCallId,
@@ -524,12 +563,7 @@ function writeRuntimeEvent(
 		);
 	}
 	if (event.type === "content_delta" && event.delta) {
-		if (!streamState?.textStarted) {
+		writeTextDelta(writer, event.delta, streamState);
-			writer.write({ type: "text-start", id: "text-1" });
-			if (streamState) streamState.textStarted = true;
-		}
-		writer.write({ type: "text-delta", id: "text-1", delta: event.delta });
-		if (streamState) streamState.textStreamed = true;
 	}
 	if (event.type === "tool_call_delta") {
 		const key =
@@ -539,6 +573,7 @@ function writeRuntimeEvent(
 				: `index:${event.tool_call_index}`);
 		if (key && !streamState?.announcedToolCallKeys.has(key)) {
 			streamState?.announcedToolCallKeys.add(key);
+			endTextPart(writer, streamState);
 			writeReasoningDelta(
 				writer,
 				{
@@ -551,26 +586,16 @@ function writeRuntimeEvent(
 		}
 	}
 	if (event.type === "final_text_start") {
-		if (!streamState?.textStarted) {
+		if (streamState) startTextPart(writer, streamState);
-			writer.write({ type: "text-start", id: "text-1" });
-			if (streamState) streamState.textStarted = true;
-		}
 	}
 	if (event.type === "final_text_delta" && event.delta) {
-		if (!streamState?.textStarted) {
+		writeTextDelta(writer, event.delta, streamState);
-			writer.write({ type: "text-start", id: "text-1" });
-			if (streamState) streamState.textStarted = true;
-		}
-		writer.write({ type: "text-delta", id: "text-1", delta: event.delta });
-		if (streamState) streamState.textStreamed = true;
 	}
 	if (event.type === "final_text_end") {
-		if (streamState?.textStarted) {
+		endTextPart(writer, streamState);
-			writer.write({ type: "text-end", id: "text-1" });
-			streamState.textStarted = false;
-		}
 	}
 	if (event.type === "tool_start" && event.tool_call_id && event.tool_name) {
+		endTextPart(writer, streamState);
 		streamState?.streamedToolCallIds.add(event.tool_call_id);
 		writer.write({
 			type: "tool-input-available",
@@ -580,6 +605,7 @@ function writeRuntimeEvent(
 		});
 	}
 	if (event.type === "tool_delta" && event.tool_call_id && event.delta) {
+		endTextPart(writer, streamState);
 		writeReasoningDelta(
 			writer,
 			{