diff --git a/SETUP.md b/SETUP.md
index c470aee5..bcd70fdc 100644
--- a/SETUP.md
+++ b/SETUP.md
@@ -64,6 +64,11 @@ Capability discovery defaults to `explicit`, preserving the zero-resident OpenPI
 
 OpenPI Web theme defaults to `system`; `light` and `dark` are explicit canonical setup choices, and the browser consumes them from each authoritative snapshot without writing a competing local preference.
 
+On Windows, OpenPI enables Pi's `clearOnShrink` compatibility behavior for
+the regular TUI so shrinking slash-command autocomplete lists do not leave
+stale rows on screen. Fullscreen TUI keeps its configured behavior. The
+native `PI_CLEAR_ON_SHRINK=0` setting remains an explicit opt-out.
+
 Legacy `footerItems` is accepted and migrated at the input boundary, but new setup writes persist only canonical `footerLines`. Configurations written by this version are not guaranteed to retain their Footer layout when read by an older OpenPI version.
 
 <!-- config-contract: capabilities.discovery suggestions.enabled suggestions.model workflows.concurrency workflows.maxAgentCalls ui.webTheme ui.showHeader ui.customFooter ui.footerStyle ui.footerLines ui.subagentResultDisplay ui.bashToolDisplay ui.fileMutationDisplay postEdit.command subagents.roleModels -->
diff --git a/extensions/windows-terminal-compat/index.ts b/extensions/windows-terminal-compat/index.ts
new file mode 100644
index 00000000..263c6ce1
--- /dev/null
+++ b/extensions/windows-terminal-compat/index.ts
@@ -0,0 +1,86 @@
+import type {
+  ExtensionAPI,
+  ExtensionContext,
+} from "@earendil-works/pi-coding-agent";
+import {
+  registerEditorLayer,
+  removeEditorLayer,
+} from "../shared/editor-layers.ts";
+
+export const WINDOWS_TERMINAL_COMPAT_LAYER = "windows-terminal-compat";
+
+type CompatibleTui = {
+  mode: "regular" | "fullscreen";
+  getClearOnShrink(): boolean;
+  setClearOnShrink(enabled: boolean): void;
+};
+
+export function shouldClearShrunkRows(
+  platform: NodeJS.Platform,
+  mode: "regular" | "fullscreen",
+  enabled = true,
+) {
+  return enabled && platform === "win32" && mode === "regular";
+}
+
+export function applyWindowsTerminalCompatibility(
+  tui: CompatibleTui,
+  platform: NodeJS.Platform,
+  enabled = true,
+) {
+  if (
+    shouldClearShrunkRows(platform, tui.mode, enabled) &&
+    !tui.getClearOnShrink()
+  ) {
+    tui.setClearOnShrink(true);
+  }
+}
+
+function install(ctx: ExtensionContext, pi: ExtensionAPI) {
+  if (ctx.mode !== "tui") {
+    return;
+  }
+
+  const windowsCompatEnabled =
+    process.platform === "win32" && process.env.PI_CLEAR_ON_SHRINK !== "0";
+  let currentTui: CompatibleTui | undefined;
+  let lastMode: CompatibleTui["mode"] | undefined;
+  const removeInputListener = ctx.ui.onTerminalInput(() => {
+    if (currentTui && currentTui.mode !== lastMode) {
+      lastMode = currentTui.mode;
+      applyWindowsTerminalCompatibility(
+        currentTui,
+        process.platform,
+        windowsCompatEnabled,
+      );
+    }
+  });
+  registerEditorLayer(pi, ctx, {
+    id: WINDOWS_TERMINAL_COMPAT_LAYER,
+    order: 100,
+    wrap: (base, tui) => {
+      currentTui = tui;
+      lastMode = tui.mode;
+      // The regular renderer otherwise leaves rows behind when autocomplete
+      // shrinks. This is a terminal redraw compatibility setting, not an
+      // editor replacement, so all existing input behavior remains intact.
+      applyWindowsTerminalCompatibility(
+        tui,
+        process.platform,
+        windowsCompatEnabled,
+      );
+      return base;
+    },
+  });
+  pi.on("session_shutdown", () => {
+    removeInputListener();
+    currentTui = undefined;
+  });
+}
+
+export default function windowsTerminalCompat(pi: ExtensionAPI) {
+  pi.on("session_start", (_event, ctx) => install(ctx, pi));
+  pi.on("session_shutdown", () => {
+    removeEditorLayer(pi, WINDOWS_TERMINAL_COMPAT_LAYER);
+  });
+}
diff --git a/tests/extensions/windows-terminal-compat/index.test.ts b/tests/extensions/windows-terminal-compat/index.test.ts
new file mode 100644
index 00000000..93ff2dbe
--- /dev/null
+++ b/tests/extensions/windows-terminal-compat/index.test.ts
@@ -0,0 +1,127 @@
+import assert from "node:assert/strict";
+import test from "node:test";
+import {
+  applyWindowsTerminalCompatibility,
+  shouldClearShrunkRows,
+} from "../../../extensions/windows-terminal-compat/index.ts";
+
+test("enables shrink cleanup for the Windows regular renderer", () => {
+  assert.equal(shouldClearShrunkRows("win32", "regular"), true);
+
+  let enabled: boolean | undefined;
+  applyWindowsTerminalCompatibility(
+    {
+      mode: "regular",
+      getClearOnShrink() {
+        return false;
+      },
+      setClearOnShrink(value) {
+        enabled = value;
+      },
+    },
+    "win32",
+  );
+
+  assert.equal(enabled, true);
+});
+
+test("does not change non-Windows or fullscreen rendering", () => {
+  assert.equal(shouldClearShrunkRows("linux", "regular"), false);
+  assert.equal(shouldClearShrunkRows("win32", "fullscreen"), false);
+
+  let calls = 0;
+  const tui = {
+    mode: "fullscreen" as const,
+    getClearOnShrink() {
+      return false;
+    },
+    setClearOnShrink() {
+      calls += 1;
+    },
+  };
+
+  applyWindowsTerminalCompatibility(tui, "win32");
+  applyWindowsTerminalCompatibility({ ...tui, mode: "regular" }, "linux");
+
+  assert.equal(calls, 0);
+});
+
+test("supports an explicit environment opt-out", () => {
+  assert.equal(shouldClearShrunkRows("win32", "regular", false), false);
+
+  let calls = 0;
+  applyWindowsTerminalCompatibility(
+    {
+      mode: "regular",
+      getClearOnShrink() {
+        return false;
+      },
+      setClearOnShrink() {
+        calls += 1;
+      },
+    },
+    "win32",
+    false,
+  );
+
+  assert.equal(calls, 0);
+});
+
+test("preserves an explicit native false renderer setting", () => {
+  let calls = 0;
+  applyWindowsTerminalCompatibility(
+    {
+      mode: "regular",
+      getClearOnShrink() {
+        return false;
+      },
+      setClearOnShrink() {
+        calls += 1;
+      },
+    },
+    "win32",
+    false,
+  );
+  assert.equal(calls, 0);
+});
+
+test("reapplies compatibility after renderer replacement", () => {
+  let listener: ((data: string) => unknown) | undefined;
+  const remove = (value: (data: string) => unknown) => {
+    listener = value;
+    return () => {
+      listener = undefined;
+    };
+  };
+  let oldClearOnShrink = false;
+  const oldRenderer = {
+    mode: "fullscreen" as const,
+    getClearOnShrink: () => oldClearOnShrink,
+    setClearOnShrink: (value: boolean) => {
+      oldClearOnShrink = value;
+    },
+  };
+  let newClearOnShrink = false;
+  const newRenderer = {
+    mode: "regular" as const,
+    getClearOnShrink: () => newClearOnShrink,
+    setClearOnShrink: (value: boolean) => {
+      newClearOnShrink = value;
+    },
+  };
+  let current: {
+    mode: "regular" | "fullscreen";
+    getClearOnShrink: () => boolean;
+    setClearOnShrink: (value: boolean) => void;
+  } = oldRenderer;
+  const unsubscribe = remove(() => {
+    applyWindowsTerminalCompatibility(current, "win32");
+  });
+  listener?.("input");
+  assert.equal(oldClearOnShrink, false);
+  current = newRenderer;
+  listener?.("input");
+  assert.equal(newClearOnShrink, true);
+  unsubscribe();
+  assert.equal(listener, undefined);
+});