Fixed Pi thread title showing prompt prefix; added message-derived draft title

Two fixes:

1. Pi thread title generation (server): Pi echoes the user message back as
   'message_update' text_delta events before streaming its actual reply. The
   collector was accumulating all deltas regardless of role, so the prompt
   prefix 'Write a concise thread title for a coding conversation...' was
   being captured as the generated title. Fix: track message_start/message_end
   role to set inAssistantMessage flag and only accumulate text_delta events
   that arrive while inside an assistant message, mirroring the same pattern
   used in PiAdapter.stream.ts. The message_end fallback path for non-streaming
   responses is also scoped to the assistant role.

2. Draft thread title UX (web): new threads showed 'New thread' in the sidebar
   until the AI title arrived — which could be several seconds after the first
   message. Now, when submitting the first message on a draft thread,
   draftTitleFromMessage() derives a provisional title from the first 25 chars
   of the user's message (stripping slash-command prefixes). This title is used
   for bootstrap.createThread.title and also passed as titleSeed so the server
   knows it is safe to replace it once the AI-generated title is ready.

Author: youpele52

apps/server/src/git/Layers/ProviderNativeThreadTitleGeneration.ts

@@ -402,36 +402,53 @@ export const generatePiThreadTitleNative = (
         new Promise<string>((resolve, reject) => {
           let collectedText = "";
           let settled = false;
+          // Track whether we are inside an assistant message so we only collect
+          // text deltas from Pi's reply — not from any user-message echoes.
+          let inAssistantMessage = false;
 
           const unsubscribe = rpcProcess.subscribe((message) => {
             if (!("type" in message)) return;
             const event = message as PiRpcStdoutEvent;
 
-            if (
+            if (event.type === "message_start") {
+              const role =
+                typeof (event as { type: "message_start"; message: Record<string, unknown> })
+                  .message.role === "string"
+                  ? (event as { type: "message_start"; message: Record<string, unknown> }).message
+                      .role
+                  : undefined;
+              inAssistantMessage = role === "assistant";
+            } else if (
               event.type === "message_update" &&
               "assistantMessageEvent" in event &&
               event.assistantMessageEvent?.type === "text_delta"
             ) {
-              collectedText += event.assistantMessageEvent.delta;
+              if (inAssistantMessage) {
+                collectedText += event.assistantMessageEvent.delta;
+              }
             } else if (event.type === "message_end") {
-              // Fallback: extract text from final message if streaming deltas weren't received
               const msg = (event as { type: "message_end"; message: Record<string, unknown> })
                 .message;
-              if (collectedText.length === 0) {
-                const content = msg.content;
-                if (typeof content === "string" && content.trim().length > 0) {
-                  collectedText = content;
-                } else if (Array.isArray(content)) {
-                  for (const part of content) {
-                    if (
-                      part &&
-                      typeof part === "object" &&
-                      "type" in part &&
-                      part.type === "text" &&
-                      "text" in part &&
-                      typeof part.text === "string"
-                    ) {
-                      collectedText += part.text;
+              const role = typeof msg.role === "string" ? msg.role : undefined;
+              if (role === "assistant") {
+                inAssistantMessage = false;
+                // Fallback: extract text from final message if streaming deltas weren't received
+                if (collectedText.length === 0) {
+                  const content = msg.content;
+                  if (typeof content === "string" && content.trim().length > 0) {
+                    collectedText = content;
+                  } else if (Array.isArray(content)) {
+                    for (const part of content) {
+                      if (
+                        part &&
+                        typeof part === "object" &&
+                        "type" in part &&
+                        part.type === "text" &&
+                        "text" in part &&
+                        typeof part.text === "string"
+                      ) {
+                        collectedText += part.text;
+                      }
                     }
                   }
                 }

apps/web/src/components/chat/view/ChatView.logic.ts

@@ -29,6 +29,25 @@ export const MAX_HIDDEN_MOUNTED_TERMINAL_THREADS = 10;
 
 export const LastInvokedScriptByProjectSchema = Schema.Record(ProjectId, Schema.String);
 
+const DRAFT_TITLE_MAX_CHARS = 25;
+
+/**
+ * Derives a short provisional thread title from the user's first message.
+ * Takes the first non-empty line, strips leading slash-command tokens, and
+ * truncates to DRAFT_TITLE_MAX_CHARS characters so the sidebar shows something
+ * meaningful before the AI-generated title arrives.
+ */
+export function draftTitleFromMessage(messageText: string): string {
+  const firstLine = messageText.trim().split(/\r?\n/)[0]?.trim() ?? "";
+  // Strip leading slash commands (e.g. "/plan ", "/default ")
+  const stripped = firstLine.replace(/^\/\w+\s*/, "").trim();
+  const candidate = stripped.length > 0 ? stripped : firstLine;
+  if (candidate.length === 0) return "New thread";
+  return candidate.length <= DRAFT_TITLE_MAX_CHARS
+    ? candidate
+    : `${candidate.slice(0, DRAFT_TITLE_MAX_CHARS - 1).trimEnd()}…`;
+}
+
 export function buildLocalDraftThread(
   threadId: ThreadId,
   draftThread: DraftThreadState,

apps/web/src/components/chat/view/ChatView.sendTurn.logic.ts

@@ -23,6 +23,7 @@ import {
   formatOutgoingPrompt,
   readFileAsDataUrl,
   cloneComposerImageForRetry,
+  draftTitleFromMessage,
 } from "./ChatView.logic";
 import { appendTerminalContextsToPrompt } from "../../../lib/terminalContext";
 import { toastManager } from "../../ui/toast";
@@ -312,14 +313,15 @@ export function useOnSend(input: UseOnSendInput) {
       }
 
       const turnAttachments = await turnAttachmentsPromise;
+      const draftTitle = isDraft ? draftTitleFromMessage(promptForSend) : undefined;
       const bootstrap =
         isDraft || baseBranchForWorktree
           ? {
               ...(isDraft
                 ? {
                     createThread: {
                       projectId: project.id,
-                      title: thread.title,
+                      title: draftTitle ?? thread.title,
                       modelSelection: threadCreateModelSelection,
                       runtimeMode: runMode,
                       interactionMode: interactMode,
@@ -357,6 +359,7 @@ export function useOnSend(input: UseOnSendInput) {
         interactionMode: interactMode,
         ...(bootstrap ? { bootstrap } : {}),
         ...(bootstrapSourceThreadId ? { bootstrapSourceThreadId } : {}),
+        ...(draftTitle ? { titleSeed: draftTitle } : {}),
         createdAt: messageCreatedAt,
       });
       if (bootstrapSourceThreadId) {