dev/configs/nixos/modules/shell/pi/patches/pi-flex-spacer.patch

diff --git a/packages/tui/src/tui.ts b/packages/tui/src/tui.ts
--- a/packages/tui/src/tui.ts	2026-08-02 00:16:00.000000000 -0400
+++ b/packages/tui/src/tui.ts	2026-08-02 00:16:00.000000000 -0400
@@ -310,7 +310,7 @@ export class TUI extends Container {
 	private cursorRow = 0; // Logical cursor row (end of rendered content)
 	private hardwareCursorRow = 0; // Actual terminal cursor row (may differ due to IME positioning)
 	private showHardwareCursor = process.env.PI_HARDWARE_CURSOR === "1";
-	private clearOnShrink = process.env.PI_CLEAR_ON_SHRINK === "1"; // Clear empty rows when content shrinks (default: off)
+	private clearOnShrink = process.env.PI_CLEAR_ON_SHRINK !== "0"; // Clear empty rows when content shrinks (default: on)
 	private maxLinesRendered = 0; // Track terminal's working area (max lines ever rendered)
 	private previousViewportTop = 0; // Track previous viewport top for resize-aware cursor moves
 	private fullRedrawCount = 0;

diff --git a/packages/coding-agent/src/core/settings-manager.ts b/packages/coding-agent/src/core/settings-manager.ts
--- a/packages/coding-agent/src/core/settings-manager.ts	2026-08-02 00:34:00.000000000 -0400
+++ b/packages/coding-agent/src/core/settings-manager.ts	2026-08-02 00:34:00.000000000 -0400
@@ -1093,11 +1093,11 @@ export class SettingsManager {
 	}
 
 	getClearOnShrink(): boolean {
-		// Settings takes precedence, then env var, then default false
+		// Settings takes precedence, then env var, then default true
 		if (this.settings.terminal?.clearOnShrink !== undefined) {
 			return this.settings.terminal.clearOnShrink;
 		}
-		return process.env.PI_CLEAR_ON_SHRINK === "1";
+		return process.env.PI_CLEAR_ON_SHRINK !== "0";
 	}
 
 	setClearOnShrink(enabled: boolean): void {

diff --git a/packages/coding-agent/src/modes/interactive/interactive-mode.ts b/packages/coding-agent/src/modes/interactive/interactive-mode.ts
--- a/packages/coding-agent/src/modes/interactive/interactive-mode.ts	2026-08-01 18:41:36.963495957 -0400
+++ b/packages/coding-agent/src/modes/interactive/interactive-mode.ts	2026-08-01 18:43:04.876341236 -0400
@@ -210,6 +210,47 @@
 	return code !== undefined && DEAD_TERMINAL_ERROR_CODES.has(code);
 }
 
+class FlexSpacerBottomLayout implements Component {
+	private readonly ui: TUI;
+	private readonly flowChildren: Component[];
+	private readonly pinnedChildren: Component[];
+
+	constructor(ui: TUI, flowChildren: Component[], pinnedChildren: Component[]) {
+		this.ui = ui;
+		this.flowChildren = flowChildren;
+		this.pinnedChildren = pinnedChildren;
+	}
+
+	invalidate(): void {
+		for (const child of [...this.flowChildren, ...this.pinnedChildren]) {
+			child.invalidate();
+		}
+	}
+
+	private renderGroup(children: Component[], width: number): string[] {
+		const lines: string[] = [];
+		for (const child of children) {
+			for (const line of child.render(width)) {
+				lines.push(line);
+			}
+		}
+		return lines;
+	}
+
+	render(width: number): string[] {
+		const flowLines = this.renderGroup(this.flowChildren, width);
+		const pinnedLines = this.renderGroup(this.pinnedChildren, width);
+		const terminalRows = this.ui.terminal.rows;
+		const spacerRows = Math.max(0, terminalRows - flowLines.length - pinnedLines.length);
+
+		return [
+			...flowLines,
+			...Array.from({ length: spacerRows }, () => ""),
+			...pinnedLines,
+		];
+	}
+}
+
 const ANTHROPIC_SUBSCRIPTION_AUTH_WARNING =
 	"Anthropic subscription auth is active. Third-party harness usage draws from extra usage and is billed per token, not your Claude plan limits. Manage extra usage at https://claude.ai/settings/usage. Disable this warning in /settings.";
 
@@ -335,6 +376,7 @@
 	private fdPath: string | undefined;
 	private editorContainer: Container;
 	private footer: FooterComponent;
+	private footerContainer: Container;
 	private footerDataProvider: FooterDataProvider;
 	// Stored so the same manager can be injected into custom editors, selectors, and extension UI.
 	private keybindings: KeybindingsManager;
@@ -477,7 +519,9 @@
 		this.editorContainer = new Container();
 		this.editorContainer.addChild(this.editor as Component);
 		this.footerDataProvider = new FooterDataProvider(this.sessionManager.getCwd());
+		this.footerContainer = new Container();
 		this.footer = new FooterComponent(this.session, this.footerDataProvider);
+		this.footerContainer.addChild(this.footer);
 		this.footer.setAutoCompactEnabled(this.session.autoCompactionEnabled);
 
 		// Load hide thinking block setting
@@ -704,19 +748,25 @@
 			console.log(theme.fg("dim", `Model scope: ${modelList}${cycleHint}`));
 		}
 
-		// Add header container as first child. Populate it after applying theme settings.
-		// Keep loaded resources before chat so restored session messages never precede them.
-		this.ui.addChild(this.headerContainer);
-		this.ui.addChild(this.loadedResourcesContainer);
-
-		this.ui.addChild(this.chatContainer);
-		this.ui.addChild(this.pendingMessagesContainer);
-		this.ui.addChild(this.statusContainer);
 		this.renderWidgets(); // Initialize with default spacer
-		this.ui.addChild(this.widgetContainerAbove);
-		this.ui.addChild(this.editorContainer);
-		this.ui.addChild(this.widgetContainerBelow);
-		this.ui.addChild(this.footer);
+		this.ui.addChild(
+			new FlexSpacerBottomLayout(
+				this.ui,
+				[
+					this.headerContainer,
+					this.loadedResourcesContainer,
+					this.chatContainer,
+				],
+				[
+					this.pendingMessagesContainer,
+					this.statusContainer,
+					this.widgetContainerAbove,
+					this.editorContainer,
+					this.widgetContainerBelow,
+					this.footerContainer,
+				],
+			),
+		);
 		this.ui.setFocus(this.editor);
 
 		this.setupKeyHandlers();
@@ -2033,25 +2083,25 @@
 			| ((tui: TUI, thm: Theme, footerData: ReadonlyFooterDataProvider) => Component & { dispose?(): void })
 			| undefined,
 	): void {
-		// Dispose existing custom footer
+		// Dispose existing custom footer
 		if (this.customFooter?.dispose) {
 			this.customFooter.dispose();
 		}
 
-		// Remove current footer from UI
+		// Remove current footer from its pinned layout slot.
 		if (this.customFooter) {
-			this.ui.removeChild(this.customFooter);
+			this.footerContainer.removeChild(this.customFooter);
 		} else {
-			this.ui.removeChild(this.footer);
+			this.footerContainer.removeChild(this.footer);
 		}
 
 		if (factory) {
 			// Create and add custom footer, passing the data provider
 			this.customFooter = factory(this.ui, theme, this.footerDataProvider);
-			this.ui.addChild(this.customFooter);
+			this.footerContainer.addChild(this.customFooter);
 		} else {
 			// Restore built-in footer
 			this.customFooter = undefined;
-			this.ui.addChild(this.footer);
+			this.footerContainer.addChild(this.footer);
 		}
 
 		this.ui.requestRender();