diff --git a/Agent.md b/Agent.md
index 1d60a245..82f90e7f 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.token; python -m emrg
 ```
 
-Python: `uv run pytest tests/ -v` (1051) — import check: `uv run python -c "from emrg.client.app import run_client"`
+Python: `uv run pytest tests/ -v` (1052) — import check: `uv run python -c "from emrg.client.app import run_client"`
 GUI: `cd emrg/gui && npm test` (259: 45 daemon_client + 20 conn-manager + 22 app-commands + 129 renderer smoke + 15 i18n + 8 integration + 3 commands + 8 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/server/prompts/upgrade_prompt.j2 b/emrg/server/prompts/upgrade_prompt.j2
index 209c05dc..4de15308 100644
--- a/emrg/server/prompts/upgrade_prompt.j2
+++ b/emrg/server/prompts/upgrade_prompt.j2
@@ -51,6 +51,16 @@ release installer" means for this version.
   `previous-version.txt`.
 - `{{ install_dir }}/bin/` launcher scripts (emrg/emrgd/emrg.cmd/emrgd.cmd
   etc.) — sync if the target tag changed them.
+- `{{ install_dir }}/bin/pyvenv.cfg` — Windows layout requirement (rant
+  2026-08-24T21:46:53, follow-up to #966): `bin\python.exe` / `bin\python3.exe`
+  are copies of the standalone interpreter and need a same-directory
+  `pyvenv.cfg` to locate the stdlib inside `bin\python-dist\`. Write it
+  idempotently with the **native absolute path** (backslashes on Windows),
+  i.e. one line: `home = {{ install_dir }}\bin\python-dist` — expand
+  {{ install_dir }} to the real path at runtime. A relative `home` fails with
+  "Fatal Python error: Failed to import encodings" — never use a relative
+  path. On POSIX layouts skip this file (the `bin/python` wrapper already
+  handles stdlib discovery).
 - GUI **must be synced too** (rant 2026-08-24T17:50: GUI packages had been
   stuck at 0.2.72 while the daemon moved on — the old "no node/npm, skip"
   reasoning was a false premise: node/npm exist on the host (asdf), they are
diff --git a/packaging/make-installer.sh b/packaging/make-installer.sh
index 05bec8c9..60eb4dbb 100755
--- a/packaging/make-installer.sh
+++ b/packaging/make-installer.sh
@@ -376,10 +376,31 @@ begin
   BroadcastEnvironmentChange;
 end;
 
+// R131: 安装后写 {app}\bin\pyvenv.cfg（rant 2026-08-24T21:46:53，#966 的
+// Windows 后续）。bin\python.exe / python3.exe 是 python-dist 解释器的复制品，
+// 需要同目录 pyvenv.cfg 才能定位标准库（CPython 在 exe 所在目录查找
+// pyvenv.cfg，home 指向 python-dist）。home 必须为绝对路径——相对路径实测
+// Fatal Python error: Failed to import encodings（venv 内 python 无法定位
+// 标准库，任务无法安装科研依赖）。pyvenv.cfg 不在 payload 里（build-runtime
+// 不生成），由安装器 ssPostInstall 写入；升级安装覆盖同内容，幂等；
+// 卸载由 [UninstallDelete] 连同 {app} 一起删除。
+procedure WritePyvenvCfg;
+var
+  CfgPath: string;
+  CfgContent: AnsiString;
+begin
+  CfgPath := ExpandConstant('{app}\bin\pyvenv.cfg');
+  CfgContent := 'home = ' + ExpandConstant('{app}\bin\python-dist') + #13#10;
+  SaveStringToFile(CfgPath, CfgContent, False);
+end;
+
 procedure CurStepChanged(CurStep: TSetupStep);
 begin
   if CurStep = ssPostInstall then
+  begin
+    WritePyvenvCfg;
     AddBinDirToPath;
+  end;
 end;
 
 procedure CurUninstallStepChanged(CurUninstallStep: TUninstallStep);
diff --git a/packaging/smoke-test.sh b/packaging/smoke-test.sh
index 30cd7b0d..33b2ce87 100755
--- a/packaging/smoke-test.sh
+++ b/packaging/smoke-test.sh
@@ -185,11 +185,24 @@ else
 fi
 
 # 14. bundled python venv（rant 2026-08-24T21:46:53：bin/python 软链 → wrapper，
-#     pyvenv.cfg home 修复）。回归用例：install python 创建 venv 后必须能导入标准库
-#     + pip 可用。Windows 用 python-dist 根 exe（bin/python.exe 复制品缺 DLL，R100）。
+#     pyvenv.cfg home 修复；Windows 后续：bin\python.exe 复制品依赖同目录
+#     bin\pyvenv.cfg 定位标准库）。回归用例：install python 创建 venv 后必须能
+#     导入标准库 + pip 可用。POSIX 走 bin/python wrapper（#966）；Windows 走
+#     bin\python.exe 本体——先复刻安装器 [Code] ssPostInstall 写的 bin\pyvenv.cfg
+#     （home = 绝对路径；相对路径实测 "Failed to import encodings"），再验证。
 say "14. bundled python venv (pyvenv.cfg home fix)"
 PY_BIN="$HOME/.emrg/install/bin/python"
-if [ -e "$HOME/.emrg/install/bin/python-dist/python.exe" ]; then
+if [ -n "${WINDIR:-}" ]; then
+  # R131：dist/runtime 未经安装器（pyvenv.cfg 由 make-installer.sh [Code] 在
+  # ssPostInstall 写入），smoke 在此复刻同款内容。有了 cfg 后 bin\python.exe
+  # 本体即可用（R100 "缺 DLL" 结论修正：DLL 同在 bin\，真正缺的是 cfg）。
+  INSTALL_BIN_WIN="$(cygpath -w "$HOME/.emrg/install/bin")"
+  printf 'home = %s\\python-dist\n' "$INSTALL_BIN_WIN" > "$HOME/.emrg/install/bin/pyvenv.cfg"
+  PY_BIN="$HOME/.emrg/install/bin/python.exe"
+  if [ ! -e "$PY_BIN" ]; then
+    PY_BIN="$HOME/.emrg/install/bin/python-dist/python.exe"
+  fi
+elif [ -e "$HOME/.emrg/install/bin/python-dist/python.exe" ]; then
   PY_BIN="$HOME/.emrg/install/bin/python-dist/python.exe"
 elif [ -e "$HOME/.emrg/install/bin/python-dist/python3.13.exe" ]; then
   PY_BIN="$HOME/.emrg/install/bin/python-dist/python3.13.exe"
diff --git a/tests/test_installer_stop.py b/tests/test_installer_stop.py
index 28d0259e..0a0cdf6b 100644
--- a/tests/test_installer_stop.py
+++ b/tests/test_installer_stop.py
@@ -312,6 +312,40 @@ def test_make_installer_iss_has_prepare_to_install():
     assert "restart the computer" in content
 
 
+def test_make_installer_iss_writes_pyvenv_cfg():
+    """rant 2026-08-24T21:46:53 — #966 的 Windows 后续：bin\\python.exe / python3.exe
+    是 python-dist 解释器的复制品，缺同目录 bin\\pyvenv.cfg → venv 内 python 无法
+    定位标准库（Could not find platform independent libraries + No module named
+    'encodings'）。修复 = 安装器 [Code] ssPostInstall 写 bin\\pyvenv.cfg
+    （home 指向 {app}\\bin\\python-dist 绝对路径；相对路径实测 "Failed to import
+    encodings"）。纯文本断言钉死接线（不执行 iscc/cmd —— macOS/CI 无 Windows）。
+    """
+    content = _read("packaging/make-installer.sh")
+    # WritePyvenvCfg 过程：SaveStringToFile 的 S 参数是 AnsiString（与 LogText 同规，
+    # 6.7.1 → 7.x 全版本一致）；UnicodeString 不匹配 → 声明 AnsiString 变量
+    assert "procedure WritePyvenvCfg;" in content
+    assert "CfgContent: AnsiString;" in content
+    assert "CfgContent: string;" not in content
+    assert "SaveStringToFile(CfgPath, CfgContent, False)" in content
+    # 写 {app}\\bin\\pyvenv.cfg，home = 绝对路径（ExpandConstant 展开 {app}）
+    assert "ExpandConstant('{app}\\bin\\pyvenv.cfg')" in content
+    assert "CfgContent := 'home = ' + ExpandConstant('{app}\\bin\\python-dist')" in content
+    # ssPostInstall 钩子：先写 cfg 再补 PATH（同一个 CurStepChanged）
+    step_src = content.split("procedure CurStepChanged")[1].split("procedure CurUninstallStepChanged")[0]
+    assert "WritePyvenvCfg;" in step_src
+    assert "AddBinDirToPath;" in step_src
+    assert step_src.index("WritePyvenvCfg;") < step_src.index("AddBinDirToPath;")
+    # smoke-test.sh：Windows 分支复刻同款 cfg（home 绝对路径）再验证 venv
+    smoke = _read("packaging/smoke-test.sh")
+    assert 'if [ -n "${WINDIR:-}" ]; then' in smoke
+    assert "printf 'home = %s\\\\python-dist\\n'" in smoke
+    assert 'PY_BIN="$HOME/.emrg/install/bin/python.exe"' in smoke
+    # upgrade_prompt.j2：本地等价安装也要写 bin\\pyvenv.cfg（绝对 home）
+    prompt = _read("emrg/server/prompts/upgrade_prompt.j2")
+    assert "bin/pyvenv.cfg" in prompt
+    assert "home = {{ install_dir }}\\bin\\python-dist" in prompt
+
+
 def test_make_installer_iss_old_python_health_check():
     """rant 2026-08-19T00:44:52 — 安装器韧性：旧版 python-dist 损坏（encodings 崩，
     v0.2.49/v0.2.50 -I 事故遗留）时，升级安装不得因坏 python 硬中止。