Keep quiet lead signal turns off-screen until they show something

web/src/task.ts

@@ -80,7 +80,7 @@ type Ctx = {
   run: Run | undefined;
   root: () => string;
   taskId: string | undefined;
-  held: HTMLElement | undefined;
+  held: DocumentFragment | undefined;
   open: boolean;
   drawn: HTMLElement[] | undefined;
   quiet: boolean;
@@ -297,7 +297,7 @@ export function mountChat(root: HTMLElement, src: ChatSource, makeHead: (rerende
     transcript.classList.toggle("running", running);
     scanner.hidden = !running;
   };
-  const putBefore = (el: HTMLElement, anchor: HTMLElement | undefined) => {
+  const putBefore = (el: Node, anchor: HTMLElement | undefined) => {
     if (sink) {
       sink.append(el);
       return;
@@ -310,11 +310,13 @@ export function mountChat(root: HTMLElement, src: ChatSource, makeHead: (rerende
   };
   const syncRunning = () => setRunning(src.session()?.state === "running" && ctx.open);
   const release = () => {
-    if (!ctx.held) {
+    const buffered = ctx.held;
+    if (!buffered) {
       return;
     }
     ctx.held = undefined;
     ctx.open = true;
+    putBefore(buffered, pending[0]?.el);
     syncRunning();
   };
   const put = (el: HTMLElement, keepHeld = false) => {
@@ -326,6 +328,10 @@ export function mountChat(root: HTMLElement, src: ChatSource, makeHead: (rerende
       release();
     }
     ctx.drawn?.push(el);
+    if (ctx.held) {
+      ctx.held.append(el);
+      return;
+    }
     putBefore(el, pending[0]?.el);
   };
   const fold = () => {
@@ -414,7 +420,7 @@ export function mountChat(root: HTMLElement, src: ChatSource, makeHead: (rerende
       sub.run = extendRun(sub.run, el, call, parent, (e) => sub.body.append(e));
       return;
     }
-    ctx.run = extendRun(ctx.run, el, call, parent, put);
+    ctx.run = extendRun(ctx.run, el, call, parent, (e) => put(e, true));
   };
 
   const extendRun = (run: Run | undefined, el: HTMLElement, call: Call | undefined, parent: string, place: (el: HTMLElement) => void): Run => {
@@ -546,7 +552,7 @@ export function mountChat(root: HTMLElement, src: ChatSource, makeHead: (rerende
           continue;
         }
         ctx.run = undefined;
-        put(el);
+        put(el, true);
         continue;
       }
       if (ev.kind === "agent.tool_call") {
@@ -591,7 +597,7 @@ export function mountChat(root: HTMLElement, src: ChatSource, makeHead: (rerende
         ctx.drawn = undefined;
       }
       if (ev.kind === "user.message" && ev.actor === "byre" && ev.owner && p["mid_turn"] !== true && p["handoff"] !== true) {
-        ctx.held = el;
+        ctx.held = document.createDocumentFragment();
         ctx.open = false;
         ctx.drawn = [];
         continue;