diff --git a/packages/client/ui-conversation/src/client/input/editor/claim-decor.ts b/packages/client/ui-conversation/src/client/input/editor/claim-decor.ts
index 7e28273305..e0ed9d3e57 100644
--- a/packages/client/ui-conversation/src/client/input/editor/claim-decor.ts
+++ b/packages/client/ui-conversation/src/client/input/editor/claim-decor.ts
@@ -43,9 +43,14 @@ export function registerClaimDecoration(editor: LexicalEditor, activeToken: () =
     }
     if (text.length > token.length) {
       // Typing at the token boundary lands in the styled node; split the
-      // overflow back out so only the token itself carries the color.
-      const [tokenNode] = node.splitText(token.length)
+      // overflow back out so only the token itself carries the color. The
+      // split copies the token style onto the overflow; it is cleared in this
+      // pass because Lexical's normalization merges same-style neighbours
+      // before the overflow's own transform runs, which would rejoin the two
+      // halves and loop until Lexical aborts the update.
+      const [tokenNode, overflow] = node.splitText(token.length)
       if (tokenNode !== undefined && tokenNode.getStyle() !== TOKEN_STYLE) tokenNode.setStyle(TOKEN_STYLE)
+      overflow?.setStyle('')
       return
     }
     if (node.getStyle() !== TOKEN_STYLE) node.setStyle(TOKEN_STYLE)
diff --git a/packages/client/ui-conversation/tests/input-scenarios.client.spec.tsx b/packages/client/ui-conversation/tests/input-scenarios.client.spec.tsx
index d3993c70df..ca03589a52 100644
--- a/packages/client/ui-conversation/tests/input-scenarios.client.spec.tsx
+++ b/packages/client/ui-conversation/tests/input-scenarios.client.spec.tsx
@@ -12,6 +12,7 @@ import './control-row-dom.ts'
 import type { GlobalStandardProps } from '@deepseek-ai/dsh-client-ui-slots'
 import { afterEach, describe, expect, it, onTestFinished, vi } from 'vitest'
 import { act, cleanup, fireEvent, render } from '@testing-library/react'
+import { $getRoot, $isElementNode, $isTextNode } from 'lexical'
 import type { SessionSnapshot } from '@deepseek-ai/dsh-api-session-controller/client'
 import { createSnapshotStore } from '@deepseek-ai/dsh-client-store'
 import { InputTriggerService } from '@deepseek-ai/dsh-client-ui-input-trigger/client'
@@ -344,6 +345,31 @@ describe('scenario H: backspace breaks the token', () => {
     expect(b.shell.snapshot.phase).toBe('plain')
   })
 
+  it('keeps text typed at the end of the claimed token when the browser inserts it natively', async () => {
+    const b = await bench()
+    b.type('/goal')
+    await vi.waitFor(() => { expect(b.controller.menu.getSnapshot().open).toBe(true) })
+    fireEvent.keyDown(b.textarea, { key: ' ', keyCode: 32 })
+    expect(b.shell.snapshot.phase).toBe('claimed')
+    b.type('/goal 发布')
+    // A caret at the token/argument boundary sits at the end of the styled
+    // token node; native insertion writes there and Lexical syncs the DOM
+    // text with setTextContent plus a caret select.
+    act(() => {
+      b.shell.editor.update(() => {
+        const paragraph = $getRoot().getFirstChild()
+        const token = $isElementNode(paragraph) ? paragraph.getFirstChild() : null
+        if (!$isTextNode(token)) throw new Error('missing token node')
+        token.setTextContent('/goal 立即')
+        token.select(8, 8)
+      }, { discrete: true })
+    })
+    expect(b.shell.snapshot.draft).toBe('/goal 立即发布')
+    expect(b.shell.snapshot.phase).toBe('claimed')
+    act(() => { b.shell.editor.update(() => {}, { discrete: true }) })
+    expect(b.view.container.querySelector('[data-lexical-text][style*="business-primary"]')?.textContent).toBe('/goal ')
+  })
+
   it('claim releases automatically; the enter after that goes through adjudication again', async () => {
     const b = await bench()
     b.type('/goal')