Add a SYSTEM_PROMPT when receiving a user_message_chunk

vscode-extension/src/acpAgentActor.ts

@@ -39,6 +39,7 @@ export interface SlashCommandInfo {
  */
 export interface AcpAgentCallbacks {
   onAgentText: (agentSessionId: string, text: string) => void;
+  onUserText: (agentSessionId: string, text: string) => void;
   onAgentComplete: (agentSessionId: string) => void;
   onRequestPermission?: (
     params: acp.RequestPermissionRequest,
@@ -171,6 +172,17 @@ class SymposiumClient implements acp.Client {
         }
         break;
       }
+      case "user_message_chunk": {
+        if (update.content.type === "text") {
+          const text = update.content.text;
+          logger.debug("user", "Text chunk", {
+            length: text.length,
+            text: text.length > 50 ? text.slice(0, 50) + "..." : text,
+          });
+          this.callbacks.onUserText(params.sessionId, update.content.text);
+        }
+        break;
+      }
     }
   }
 

vscode-extension/src/chatViewProvider.ts

@@ -126,6 +126,32 @@ export class ChatViewProvider implements vscode.WebviewViewProvider {
           });
         }
       },
+      onUserText: (agentSessionId, text) => {
+        const receiveTime = Date.now();
+        const tabId = this.#agentSessionToTab.get(agentSessionId);
+        if (tabId) {
+          // Capture for testing if enabled
+          if (this.#testResponseCapture.has(tabId)) {
+            this.#testResponseCapture.get(tabId)!.push(text);
+          }
+
+          logger.debug("perf", "Received chunk from user", {
+            receiveTime,
+            textLength: text.length,
+          });
+          this.#sendToWebview({
+            type: "user-text",
+            tabId,
+            text,
+            timestamp: receiveTime,
+          });
+          const sendTime = Date.now();
+          logger.debug("perf", "Sent chunk to webview", {
+            sendTime,
+            delay: sendTime - receiveTime,
+          });
+        }
+      },
       onAgentComplete: (agentSessionId) => {
         const tabId = this.#agentSessionToTab.get(agentSessionId);
         if (tabId) {

vscode-extension/src/symposium-webview.ts

@@ -687,6 +687,27 @@ window.addEventListener("message", (event: MessageEvent) => {
     console.log(
       `[PERF] Append: ${appendEnd - appendStart}ms, UI update: ${uiUpdateEnd - uiUpdateStart}ms, total: ${uiUpdateEnd - receiveTime}ms`,
     );
+  } else if (message.type === "user-text") {
+    const extensionDelay = message.timestamp
+      ? receiveTime - message.timestamp
+      : "unknown";
+    console.log(
+      `[PERF] Webview received chunk at ${receiveTime}, extension->webview delay=${extensionDelay}ms, length=${message.text.length}`,
+    );
+
+    // We don't expect a stream here - so just add an item
+    const newMessageId = uuidv4();
+    mynahUI.addChatItem(message.tabId, {
+      type: ChatItemType.SYSTEM_PROMPT,
+      body: message.text,
+    });
+
+    // Assume that all messages here count as *prompts*
+    mynahUI.updateStore(message.tabId, {
+      loadingChat: true,
+    });
+
+    saveState();
   } else if (message.type === "agent-complete") {
     // Hide loading/thinking indicator
     mynahUI.updateStore(message.tabId, {