diff --git a/packages/tui/src/overlay-layout.ts b/packages/tui/src/overlay-layout.ts
index 0110f0f57..88cf527e7 100644
--- a/packages/tui/src/overlay-layout.ts
+++ b/packages/tui/src/overlay-layout.ts
@@ -12,7 +12,7 @@ import type {
 } from "./overlay-types.js";
 import { tryRender } from "./render-guard.js";
 import { isImageLine } from "./terminal-image.js";
-import { CURSOR_MARKER } from "./tui.js";
+import { CURSOR_MARKER } from "./overlay-types.js";
 import {
 	applyBackgroundToLine,
 	extractSegments,
diff --git a/packages/tui/src/overlay-types.ts b/packages/tui/src/overlay-types.ts
index bc9ac00f8..0f45f3e8b 100644
--- a/packages/tui/src/overlay-types.ts
+++ b/packages/tui/src/overlay-types.ts
@@ -1,7 +1,19 @@
 /**
  * Overlay sizing, anchoring, and handle types for layered TUI content.
+ *
+ * Also hosts CURSOR_MARKER (moved here from ./tui.ts to break the
+ * tui ↔ overlay-layout circular import — both files already import
+ * this module, so it's the natural shared landing zone).
  */
 
+/**
+ * Cursor position marker — APC (Application Program Command) sequence.
+ * This is a zero-width escape sequence that terminals ignore.
+ * Components emit this at the cursor position when focused.
+ * TUI finds and strips this marker, then positions the hardware cursor there.
+ */
+export const CURSOR_MARKER = "\x1b_sf:c\x07";
+
 /** Margin configuration for overlays */
 export interface OverlayMargin {
 	top?: number;
diff --git a/packages/tui/src/tui.ts b/packages/tui/src/tui.ts
index 1e1511262..8617392a4 100644
--- a/packages/tui/src/tui.ts
+++ b/packages/tui/src/tui.ts
@@ -83,13 +83,11 @@ export function isFocusable(
 	return component !== null && "focused" in component;
 }
 
-/**
- * Cursor position marker - APC (Application Program Command) sequence.
- * This is a zero-width escape sequence that terminals ignore.
- * Components emit this at the cursor position when focused.
- * TUI finds and strips this marker, then positions the hardware cursor there.
- */
-export const CURSOR_MARKER = "\x1b_sf:c\x07";
+// CURSOR_MARKER moved to ./overlay-types.ts to break the
+// tui ↔ overlay-layout circular import. Re-exported here so
+// existing call sites that import { CURSOR_MARKER } from "./tui.js"
+// keep working.
+export { CURSOR_MARKER } from "./overlay-types.js";
 
 export type {
 	OverlayAnchor,