diff --git a/Agent.md b/Agent.md
index a8caef3f..6a0b3b75 100644
--- a/Agent.md
+++ b/Agent.md
@@ -118,7 +118,7 @@ Community needs voiced in HN agent-UI discussions map directly to EMRG's design:
 pkill -f "emrg.server"; rm -f ~/.emrg/emrgd.port; python -m emrg
 ```
 
-Python: `uv run pytest tests/ -v` (801) — import check: `uv run python -c "from emrg.client.app import run_client"`
+Python: `uv run pytest tests/ -v` (804) — import check: `uv run python -c "from emrg.client.app import run_client"`
 GUI: `cd emrg/gui && npm test` (244: 44 daemon_client + 19 conn-manager + 22 app-commands + 119 renderer smoke + 16 i18n + 7 integration + 3 commands + 5 build-config + 7 gui-state + 2 tool-group) — syntax: `node --check main.js preload.js daemon_client.js renderer/js/*.js`
 CI: `uv run pytest` (ubuntu + **windows-2025 matrix** — Windows pytest 回归在 PR CI 即失败，v0.2.29 教训 #725) + GUI tests + **actionlint workflow lint** (`rhysd/actionlint@v1.7.12` gate, #444 — workflow 解析错误在 PR CI 即失败，如 `if:` secrets 上下文)
 Re-trigger: `scripts/re-trigger-ci.sh [branch]` (workflow_dispatch, #527 — 替代空 commit 重触发：Actions outage 会整段丢弃 push 事件，dispatch 走 API 路径不受影响)
diff --git a/emrg/client/python_tui/terminal.py b/emrg/client/python_tui/terminal.py
index 37720b45..47fdb410 100644
--- a/emrg/client/python_tui/terminal.py
+++ b/emrg/client/python_tui/terminal.py
@@ -23,6 +23,7 @@
 
 from emrg.client.python_tui.buffer import Buffer, CharPool, HyperlinkPool, StylePool, diff_buffers
 from emrg.client.python_tui.output import (
+    CLEAR_SCREEN,
     CURSOR_HIDE,
     CURSOR_SHOW,
     CURSOR_HOME,
@@ -142,6 +143,10 @@ def __post_init__(self) -> None:
         )
         self._rendered_cache: dict[str, list[object]] = {}
         self._scrollback_lines_pushed: int = 0
+        # 上次渲染宽度（rant 2026-08-14T11:47:11）：窗口缩窄时终端屏幕每行右侧的旧字符
+        # 不会被 diff 清除（diff_buffers 只比较 min(prev_w, curr_w) 列，且 Buffer.resize
+        # 缩窄已物理截断旧宽度信息）→ render 检测到缩窄时先 CLEAR_SCREEN 再全量重绘。
+        self._last_render_width: int = self.caps.width
 
     @property
     def viewport_height(self) -> int:
@@ -215,6 +220,16 @@ def render(self, full: bool = False) -> None:
         width = self.viewport.viewport_width
         ctx = RenderContext(width=width)
 
+        # 宽度缩窄 → 终端屏幕右侧残留旧字符（diff 只覆盖新宽度；Buffer.resize 缩窄已
+        # 丢弃旧宽度信息，diff_buffers 无从清除）。先清屏 + 清 front buffer 强制全量
+        # 重绘，杜绝残留叠加（rant 2026-08-14T11:47:11）。
+        if width < self._last_render_width:
+            sys.stdout.write(CLEAR_SCREEN)
+            if self._front_buffer:
+                self._front_buffer.clear()
+            full = True
+        self._last_render_width = width
+
         # Cache last rendered output per widget so dirty=False doesn't blank it
 
         def _get_lines(name: str) -> list[object]:
diff --git a/tests/test_terminal_render.py b/tests/test_terminal_render.py
new file mode 100644
index 00000000..b7171c4e
--- /dev/null
+++ b/tests/test_terminal_render.py
@@ -0,0 +1,80 @@
+"""Unit tests for Terminal render — 宽度缩窄残留清除（rant 2026-08-14T11:47:11）。
+
+窗口缩窄时终端屏幕每行右侧的旧字符不会被 diff 清除（diff_buffers 只比较
+min(prev_w, curr_w) 列，且 Buffer.resize 缩窄已物理截断旧宽度信息）→
+render 检测到缩窄时先 CLEAR_SCREEN 再全量重绘。本测试验证该行为。
+"""
+
+from __future__ import annotations
+
+import io
+import sys
+from contextlib import redirect_stdout
+
+import pytest
+
+# 依赖 posix 路径（raw mode / termios 守卫），Windows 跳过（同 test_app_widgets）
+pytestmark = pytest.mark.skipif(sys.platform == "win32", reason="Terminal 渲染测试依赖 POSIX 路径")
+
+from emrg.client.python_tui.output import CLEAR_SCREEN
+from emrg.client.python_tui.terminal import Terminal
+from emrg.client.python_tui.widgets.base import Line, RenderContext, Span
+
+
+class FakeWidget:
+    """Minimal widget: renders `width` chars per line."""
+
+    def __init__(self) -> None:
+        self.dirty = True
+
+    def render(self, ctx: RenderContext) -> list[Line]:
+        return [Line(spans=[Span(text="x" * ctx.width)])]
+
+
+def _set_width(term: Terminal, width: int) -> None:
+    """Force terminal width (SIGWINCH path would probe real tty — not usable in tests)."""
+    term.caps.width = width
+    term.viewport.resize(term.caps.height, width)
+
+
+def _render(term: Terminal) -> str:
+    buf = io.StringIO()
+    with redirect_stdout(buf):
+        term.render(full=True)
+    return buf.getvalue()
+
+
+def test_render_shrink_emits_clear_screen():
+    """缩窄 40 → 20：输出必须先 CLEAR_SCREEN（右侧残留清除）。"""
+    term = Terminal()
+    term.mount(chat=FakeWidget())
+    _set_width(term, 40)
+    _render(term)  # 建立 _last_render_width = 40
+
+    _set_width(term, 20)
+    out = _render(term)
+
+    assert CLEAR_SCREEN in out
+
+
+def test_render_same_width_no_clear_screen():
+    """同宽两次渲染：无 CLEAR_SCREEN（避免无谓闪烁）。"""
+    term = Terminal()
+    term.mount(chat=FakeWidget())
+    _set_width(term, 40)
+    _render(term)
+
+    out = _render(term)
+    assert CLEAR_SCREEN not in out
+
+
+def test_render_grow_no_clear_screen():
+    """拉宽 40 → 60：无 CLEAR_SCREEN（新增列由 diff 覆盖，无需清屏）。"""
+    term = Terminal()
+    term.mount(chat=FakeWidget())
+    _set_width(term, 40)
+    _render(term)
+
+    _set_width(term, 60)
+    out = _render(term)
+    assert CLEAR_SCREEN not in out