diff --git a/Agent.md b/Agent.md
index 7a2edacc..a047db65 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` (929) — import check: `uv run python -c "from emrg.client.app import run_client"`
+Python: `uv run pytest tests/ -v` (933) — import check: `uv run python -c "from emrg.client.app import run_client"`
 GUI: `cd emrg/gui && npm test` (257: 45 daemon_client + 19 conn-manager + 22 app-commands + 129 renderer smoke + 16 i18n + 7 integration + 3 commands + 7 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/_stop_all.py b/emrg/_stop_all.py
index 99eda2a9..4035107e 100644
--- a/emrg/_stop_all.py
+++ b/emrg/_stop_all.py
@@ -53,6 +53,7 @@
 import subprocess
 import sys
 import time
+from datetime import datetime
 from pathlib import Path
 
 # Build stamp printed at the start of every run so the operator can tell at a
@@ -999,6 +1000,54 @@ def _pythonpath_install_warning(line: str) -> str | None:
     return None
 
 
+class _Tee:
+    """Duplicate write()/flush() to BOTH the original stdout and a log file
+    (rant 2026-08-18T11:20:54). The Inno installer redirects stop_all stdout
+    to a random temp dir ({tmp}\\stop_all.log) that is deleted when the
+    install ends or is cancelled — the tee keeps a persistent fixed-path copy
+    (~/.emrg/logs/stop_all-<ts>.log) for post-mortem forensics. All existing
+    print() calls keep working untouched (they write to sys.stdout, which is
+    replaced with a _Tee during stop_all)."""
+
+    def __init__(self, orig, f):
+        self.orig = orig
+        self.f = f
+
+    def write(self, data):
+        self.orig.write(data)
+        self.f.write(data)
+        # Crash-safe: if the installer force-kills this process mid-write,
+        # append-mode + per-write flush guarantees the fixed-path copy has
+        # everything printed so far (rant: 不依赖 finally).
+        self.f.flush()
+        return len(data)
+
+    def flush(self):
+        self.orig.flush()
+        self.f.flush()
+
+    def isatty(self):
+        return self.orig.isatty() if hasattr(self.orig, "isatty") else False
+
+    def fileno(self):
+        return self.orig.fileno()
+
+
+def _open_stop_log() -> object | None:
+    """Open the fixed-path dual-write log (rant 2026-08-18T11:20:54):
+    ``~/.emrg/logs/stop_all-YYYYMMDD-HHMMSS.log`` (local time; the timestamp
+    name makes concurrent stop_all runs naturally isolated). Returns the file
+    object or None on any failure — best-effort, never breaks the stop flow.
+    The handle closes naturally at process exit (no finally dependency)."""
+    try:
+        d = os.path.join(os.path.expanduser("~"), ".emrg", "logs")
+        os.makedirs(d, exist_ok=True)
+        ts = datetime.now().strftime("%Y%m%d-%H%M%S")
+        return open(os.path.join(d, f"stop_all-{ts}.log"), "a", encoding="utf-8")
+    except OSError:
+        return None
+
+
 def _step_plan() -> list[tuple[str, object]]:
     """Ordered stop steps. Clients (GUI/TUI) FIRST, daemon LAST (rant
     2026-08-17T14:15:33): both clients auto-spawn the daemon when it
@@ -1030,6 +1079,15 @@ def stop_all() -> int:
     ``ERROR <step>: <reason>`` and the run continues to the final exit code).
     """
     t0 = time.monotonic()
+    # Dual-write log to a fixed path (rant 2026-08-18T11:20:54): the Inno
+    # {tmp} redirect vanishes when the install ends/cancels — tee a persistent
+    # copy to ~/.emrg/logs/stop_all-<ts>.log. Every print below automatically
+    # lands in both. The line is also printed so the Inno-side log and the
+    # operator both see the fixed location.
+    _log_f = _open_stop_log()
+    if _log_f is not None:
+        sys.stdout = _Tee(sys.stdout, _log_f)
+        print(f"emrg stop: log also written to {_log_f.name}")
     print(
         f"emrg stop: stop_all.py {_STOP_ALL_STAMP} | "
         f"python {platform.python_version()} {platform.system()}-{platform.machine()} "
diff --git a/tests/test_stop_all.py b/tests/test_stop_all.py
index af874edf..9265fa45 100644
--- a/tests/test_stop_all.py
+++ b/tests/test_stop_all.py
@@ -39,7 +39,7 @@ def test_no_nonstdlib_imports(self):
         allowed = {
             "base64", "json", "os", "re", "secrets", "signal", "socket",
             "subprocess", "sys", "time", "pathlib", "platform", "ctypes", "ast",
-            "pytest", "annotations", "__future__", "winreg",
+            "pytest", "annotations", "__future__", "winreg", "datetime",
         }
         for node in ast.walk(tree):
             if isinstance(node, ast.Import):
@@ -956,3 +956,62 @@ def test_install_warning_positive_and_negative(self):
         # unrelated install\lib path must NOT warn (pm25coder review note, PR #832)
         assert _stop_all._pythonpath_install_warning(
             r"PYTHONPATH(User)=C:\python\install\lib") is None
+
+
+# ── Fixed-path dual-write log (rant 2026-08-18T11:20:54) ────────
+
+class TestTeeDualWrite:
+    def test_tee_writes_to_both(self):
+        class _FakeFile:
+            def __init__(self):
+                self.data = []
+
+            def write(self, d):
+                self.data.append(d)
+
+            def flush(self):
+                pass
+
+        orig = _FakeFile()
+        logf = _FakeFile()
+        tee = _stop_all._Tee(orig, logf)
+        tee.write("line1\n")
+        tee.write("line2\n")
+        tee.flush()
+        assert orig.data == ["line1\n", "line2\n"]
+        assert logf.data == ["line1\n", "line2\n"]
+
+    def test_open_stop_log_creates_logs_dir(self, monkeypatch, tmp_path):
+        """~/.emrg/logs is created and the file matches the timestamp pattern
+        (stop_all-YYYYMMDD-HHMMSS.log)."""
+        monkeypatch.setattr(_stop_all.os.path, "expanduser", lambda _: str(tmp_path))
+        f = _stop_all._open_stop_log()
+        assert f is not None
+        name = f.name
+        f.close()
+        assert str(tmp_path / ".emrg" / "logs") in name
+        import re
+        assert re.search(r"stop_all-\d{8}-\d{6}\.log$", name), name
+
+    def test_open_stop_log_oserror_returns_none(self, monkeypatch, tmp_path):
+        def boom(*a, **k):
+            raise OSError("cannot create logs dir")
+
+        monkeypatch.setattr(_stop_all.os, "makedirs", boom)
+        assert _stop_all._open_stop_log() is None
+
+    def test_stop_all_prints_tee_path(self, monkeypatch, tmp_path, capsys):
+        """stop_all() with a tee open prints the fixed-path line; stdout output
+        still flows (POSIX regression: emrg stop output unchanged)."""
+        monkeypatch.setattr(_stop_all, "is_win", lambda: False)
+        monkeypatch.setattr(_stop_all.os.path, "expanduser", lambda _: str(tmp_path))
+        monkeypatch.setattr(_stop_all, "stop_gui", lambda: None)
+        monkeypatch.setattr(_stop_all, "stop_tui", lambda: None)
+        monkeypatch.setattr(_stop_all, "stop_daemon", lambda: None)
+        monkeypatch.setattr(_stop_all, "_stop_scan_pids", lambda own: [])
+        monkeypatch.setattr(_stop_all, "verify", lambda: [])
+        assert _stop_all.stop_all() == 0
+        out = capsys.readouterr().out
+        assert "log also written to" in out
+        assert str(tmp_path / ".emrg" / "logs") in out
+        assert "exit code 0 (clean)" in out