diff --git a/apps/web/src/lib/assistantTextSelection.test.ts b/apps/web/src/lib/assistantTextSelection.test.ts
index 31f00225588a..f4725af73ad1 100644
--- a/apps/web/src/lib/assistantTextSelection.test.ts
+++ b/apps/web/src/lib/assistantTextSelection.test.ts
@@ -56,6 +56,13 @@ class SelectionNode {
   get nodeType() {
     return this.tagName === "#text" ? 3 : 1;
   }
+  get ownerDocument() {
+    // `user-select: none` inherits, like Chromium's computed style.
+    const getComputedStyle = (element: SelectionNode) => ({
+      userSelect: element.closest("[data-select-none]") ? "none" : "auto",
+    });
+    return { defaultView: { getComputedStyle } };
+  }
   get length() {
     return this.data.length;
   }
@@ -259,6 +266,22 @@ describe("captureAssistantTextSelection", () => {
     expect(capture(source, nativeSelection([quote, 0], [timestampText, 1]))).toBeNull();
   });
 
+  it("captures a triple-clicked response that ends before a tool row and the next response", () => {
+    const quote = textNode("Recording your answers in the session note:");
+    const source = assistantSource(new SelectionNode("P").append(quote));
+    const nextParagraph = new SelectionNode("P").append(textNode("1. What it means."));
+    const viewport = new SelectionNode("MAIN").append(
+      source,
+      new SelectionNode("DIV", "", { "data-select-none": "" }).append(textNode("echo ok")),
+      new SelectionNode("H3", "", { "data-select-none": "" }).append(textNode("T3 Code")),
+      assistantSource(nextParagraph),
+    );
+
+    expect(capture(viewport, nativeSelection([quote, 0], [nextParagraph, 0]))?.selector).toEqual(
+      selector(quote.data),
+    );
+  });
+
   it("does not attribute an empty starting endpoint to the previous response", () => {
     const previous = textNode("Previous response.");
     const quote = textNode("Selected response.");
diff --git a/apps/web/src/lib/assistantTextSelection.ts b/apps/web/src/lib/assistantTextSelection.ts
index f118555f3eac..1f388b2e14f9 100644
--- a/apps/web/src/lib/assistantTextSelection.ts
+++ b/apps/web/src/lib/assistantTextSelection.ts
@@ -189,13 +189,21 @@ function isUsableRange(root: HTMLElement, range: Range): boolean {
   return true;
 }
 
+function isUnselectable(text: Text): boolean {
+  const element = text.parentElement;
+  const view = element?.ownerDocument?.defaultView;
+  return !!element && !!view && view.getComputedStyle(element).userSelect === "none";
+}
+
 function selectedTextBoundary(range: Range, node: Node, last: boolean): Text | null {
   if (!range.intersectsNode(node)) return null;
   if (node.nodeType === 3) {
     const text = node as Text;
     const start = node === range.startContainer ? range.startOffset : 0;
     const end = node === range.endContainer ? range.endOffset : text.length;
-    return start < end ? text : null;
+    // Triple-click ranges run through unselectable rows (tool calls, timestamps,
+    // author headings) into the next response; that text is not selected.
+    return start < end && !isUnselectable(text) ? text : null;
   }
   for (
     let child = last ? node.lastChild : node.firstChild;