diff --git a/src/renderer/src/components/native-chat/native-chat-pending-occurrence.ts b/src/renderer/src/components/native-chat/native-chat-pending-occurrence.ts
index a994ecf8da7c..741423e98c13 100644
--- a/src/renderer/src/components/native-chat/native-chat-pending-occurrence.ts
+++ b/src/renderer/src/components/native-chat/native-chat-pending-occurrence.ts
@@ -114,9 +114,8 @@ export function matchingNativeChatUserTexts(
 }
 
 /**
- * How many leading pending texts concatenate exactly to `userText`.
- * Covers rapid-send glue ("joke"+"continue" → "jokecontinue") without matching
- * unrelated prefixes ("hi" ↛ "history").
+ * How many leading pending texts concatenate exactly to `userText`, with or
+ * without one normalized whitespace separator at each send boundary.
  */
 export function countLeadingPendingTextsGluedToUserText(
   pendingTexts: readonly string[],
@@ -125,17 +124,23 @@ export function countLeadingPendingTextsGluedToUserText(
   if (pendingTexts.length === 0 || userText.length === 0) {
     return 0
   }
-  let combined = ''
+  let candidates = new Set<string>()
   for (let index = 0; index < pendingTexts.length; index += 1) {
     const piece = pendingTexts[index]
     if (!piece) {
       return 0
     }
-    combined += piece
-    if (combined === userText) {
+    const next =
+      index === 0
+        ? new Set([piece])
+        : new Set(
+            [...candidates].flatMap((candidate) => [candidate + piece, `${candidate} ${piece}`])
+          )
+    candidates = new Set([...next].filter((candidate) => userText.startsWith(candidate)))
+    if (candidates.has(userText)) {
       return index + 1
     }
-    if (!userText.startsWith(combined)) {
+    if (candidates.size === 0) {
       return 0
     }
   }
diff --git a/src/renderer/src/components/native-chat/native-chat-pending.test.ts b/src/renderer/src/components/native-chat/native-chat-pending.test.ts
index 75b2c3d34c77..121868550bd1 100644
--- a/src/renderer/src/components/native-chat/native-chat-pending.test.ts
+++ b/src/renderer/src/components/native-chat/native-chat-pending.test.ts
@@ -189,6 +189,36 @@ describe('prunePendingSends', () => {
     ).toEqual([])
   })
 
+  it('prunes optimistic sends glued with a retained whitespace separator', () => {
+    const pending = [pendingOf('p1', 'tell me a joke '), pendingOf('p2', 'continue')]
+    expect(
+      prunePendingSends(pending, [
+        userMessage('u1', 'tell me a joke continue'),
+        assistantMessage('a1', 'a joke')
+      ])
+    ).toEqual([])
+  })
+
+  it('matches mixed separated and separator-less rapid sends', () => {
+    const pending = [pendingOf('p1', 'first'), pendingOf('p2', 'second '), pendingOf('p3', 'third')]
+    expect(
+      prunePendingSends(pending, [
+        userMessage('u1', 'firstsecond third'),
+        assistantMessage('a1', 'done')
+      ])
+    ).toEqual([])
+  })
+
+  it('prunes repeated prompts represented by one separated transcript turn', () => {
+    const pending = [pendingOf('p1', 'repeat '), pendingOf('p2', 'repeat')]
+    expect(
+      prunePendingSends(pending, [
+        userMessage('u1', 'repeat repeat'),
+        assistantMessage('a1', 'done')
+      ])
+    ).toEqual([])
+  })
+
   it('does not treat an unrelated longer user turn as a glued match', () => {
     const pending = [pendingOf('p1', 'hi')]
     expect(
@@ -198,6 +228,16 @@ describe('prunePendingSends', () => {
       ])
     ).toEqual(pending)
   })
+
+  it('does not accept a separated glue candidate that is only a user-text prefix', () => {
+    const pending = [pendingOf('p1', 'hi'), pendingOf('p2', 'story')]
+    expect(
+      prunePendingSends(pending, [
+        userMessage('u1', 'hi story continued'),
+        assistantMessage('a1', 'ok')
+      ])
+    ).toEqual(pending)
+  })
 })
 
 describe('pendingSendsAsMessages', () => {