diff --git a/apps/desktop/src/lib/composer-input-sanitize.test.ts b/apps/desktop/src/lib/composer-input-sanitize.test.ts
new file mode 100644
index 000000000..2695f942e
--- /dev/null
+++ b/apps/desktop/src/lib/composer-input-sanitize.test.ts
@@ -0,0 +1,51 @@
+import { describe, expect, it } from 'vitest'
+
+import {
+  collapseRepeatedInputArtifacts,
+  sanitizeComposerInput,
+  stripLeakedBracketedPasteWrappers
+} from './composer-input-sanitize'
+
+describe('stripLeakedBracketedPasteWrappers', () => {
+  it('leaves plain text unchanged', () => {
+    expect(stripLeakedBracketedPasteWrappers('hello world')).toBe('hello world')
+  })
+
+  it('strips canonical escape wrappers', () => {
+    expect(stripLeakedBracketedPasteWrappers('\x1b[200~hello\x1b[201~')).toBe('hello')
+  })
+
+  it('keeps embedded literal bracket forms', () => {
+    const text = 'literal[200~tag and literal[201~tag should stay'
+    expect(stripLeakedBracketedPasteWrappers(text)).toBe(text)
+  })
+})
+
+describe('collapseRepeatedInputArtifacts', () => {
+  it('removes the desktop corruption tail from #62557', () => {
+    const prefix = '需要时随时叫我。'
+    const tail = '[e~[[e' + '~[[e'.repeat(20)
+    expect(collapseRepeatedInputArtifacts(prefix + tail)).toBe(prefix)
+  })
+
+  it('preserves a mid-string marker followed by valid suffix', () => {
+    const text = 'notes ~[[e more text here'
+    expect(collapseRepeatedInputArtifacts(text)).toBe(text)
+  })
+
+  it('preserves trailing punctuation that is not the corruption signature', () => {
+    expect(collapseRepeatedInputArtifacts('wait....')).toBe('wait....')
+  })
+
+  it('does not strip when fewer than minRepeats markers appear at the tail', () => {
+    const text = 'hello~[[e~[[e'
+    expect(collapseRepeatedInputArtifacts(text)).toBe(text)
+  })
+})
+
+describe('sanitizeComposerInput', () => {
+  it('normalizes wrappers and repeated artifact tails together', () => {
+    const corrupted = 'hello[' + '~[[e'.repeat(8)
+    expect(sanitizeComposerInput(corrupted)).toBe('hello')
+  })
+})
diff --git a/tests/hermes_cli/test_input_sanitize.py b/tests/hermes_cli/test_input_sanitize.py
new file mode 100644
index 000000000..b0e86e099
--- /dev/null
+++ b/tests/hermes_cli/test_input_sanitize.py
@@ -0,0 +1,51 @@
+"""Tests for shared user prompt input sanitization."""
+
+from hermes_cli.input_sanitize import (
+    collapse_repeated_input_artifacts,
+    sanitize_user_prompt_text,
+    strip_leaked_bracketed_paste_wrappers,
+)
+
+
+class TestStripLeakedBracketedPasteWrappers:
+    def test_plain_text_unchanged(self):
+        assert strip_leaked_bracketed_paste_wrappers("hello world") == "hello world"
+
+    def test_strips_canonical_escape_wrappers(self):
+        assert strip_leaked_bracketed_paste_wrappers("\x1b[200~hello\x1b[201~") == "hello"
+
+    def test_strips_visible_caret_escape_wrappers(self):
+        assert strip_leaked_bracketed_paste_wrappers("^[[200~hello^[[201~") == "hello"
+
+    def test_does_not_strip_non_wrapper_bracket_forms_in_normal_text(self):
+        text = "literal[200~tag and literal[201~tag should stay"
+        assert strip_leaked_bracketed_paste_wrappers(text) == text
+
+
+class TestCollapseRepeatedInputArtifacts:
+    def test_issue_62557_corruption_tail(self):
+        prefix = "需要时随时叫我。"
+        tail = "[e~[[e" + "~[[e" * 20
+        assert collapse_repeated_input_artifacts(prefix + tail) == prefix
+
+    def test_plain_text_unchanged(self):
+        text = "build00~tag should stay"
+        assert collapse_repeated_input_artifacts(text) == text
+
+    def test_mid_string_marker_followed_by_suffix_preserved(self):
+        text = "notes ~[[e more text here"
+        assert collapse_repeated_input_artifacts(text) == text
+
+    def test_trailing_punctuation_preserved(self):
+        assert collapse_repeated_input_artifacts("wait....") == "wait...."
+
+    def test_insufficient_tail_repeats_preserved(self):
+        text = "hello~[[e~[[e"
+        assert collapse_repeated_input_artifacts(text) == text
+
+
+class TestSanitizeUserPromptText:
+    def test_combines_wrapper_strip_and_tail_collapse(self):
+        prefix = "hello["
+        corrupted = prefix + "~[[e" * 8
+        assert sanitize_user_prompt_text(corrupted) == "hello"
diff --git a/tests/test_tui_gateway_server.py b/tests/test_tui_gateway_server.py
index f117af57a..3b591156e 100644
--- a/tests/test_tui_gateway_server.py
+++ b/tests/test_tui_gateway_server.py
@@ -5093,6 +5093,51 @@ def test_prompt_submit_history_version_mismatch_surfaces_warning(monkeypatch):
         server._sessions.pop("sid", None)
 
 
+def test_prompt_submit_sanitizes_bracketed_paste_before_agent(monkeypatch):
+    """prompt.submit must sanitize corrupted user text before run_conversation."""
+    captured: dict[str, str] = {}
+
+    class _Agent:
+        def run_conversation(
+            self, prompt, conversation_history=None, stream_callback=None
+        ):
+            captured["prompt"] = prompt
+            return {
+                "final_response": "ok",
+                "messages": [{"role": "assistant", "content": "ok"}],
+            }
+
+    class _ImmediateThread:
+        def __init__(self, target=None, daemon=None, **kw):
+            self._target = target
+
+        def start(self):
+            self._target()
+
+    corrupted = "hello[" + "~[[e" * 8
+    server._sessions["sid"] = _session(agent=_Agent())
+    try:
+        monkeypatch.setattr(server.threading, "Thread", _ImmediateThread)
+        monkeypatch.setattr(server, "_get_usage", lambda _a: {})
+        monkeypatch.setattr(server, "render_message", lambda _t, _c: "")
+        monkeypatch.setattr(server, "_emit", lambda *a: None)
+        monkeypatch.setattr(server, "_start_agent_build", lambda *a, **k: None)
+        monkeypatch.setattr(server, "_ensure_session_db_row", lambda *a, **k: None)
+        monkeypatch.setattr(server, "_persist_branch_seed", lambda *a, **k: None)
+
+        resp = server.handle_request(
+            {
+                "id": "1",
+                "method": "prompt.submit",
+                "params": {"session_id": "sid", "text": corrupted},
+            }
+        )
+        assert resp.get("result"), f"got error: {resp.get('error')}"
+        assert captured["prompt"] == "hello"
+    finally:
+        server._sessions.pop("sid", None)
+
+
 def test_prompt_submit_history_version_match_persists_normally(monkeypatch):
     """Regression guard: the backstop does not affect the happy path."""