diff --git a/packages/coding-agent/src/modes/utils/ui-helpers.ts b/packages/coding-agent/src/modes/utils/ui-helpers.ts
index 906590ebd..632095fa8 100644
--- a/packages/coding-agent/src/modes/utils/ui-helpers.ts
+++ b/packages/coding-agent/src/modes/utils/ui-helpers.ts
@@ -209,6 +209,7 @@ export class UiHelpers {
 		sessionContext: SessionContext,
 		options: { updateFooter?: boolean; populateHistory?: boolean } = {},
 	): void {
+		this.ctx.optimisticUserMessageSignature = undefined;
 		this.ctx.pendingTools.clear();
 
 		if (options.updateFooter) {
diff --git a/packages/coding-agent/test/interactive-mode-status.test.ts b/packages/coding-agent/test/interactive-mode-status.test.ts
index 7de45651b..82a75cd04 100644
--- a/packages/coding-agent/test/interactive-mode-status.test.ts
+++ b/packages/coding-agent/test/interactive-mode-status.test.ts
@@ -1,5 +1,6 @@
 import { beforeAll, describe, expect, test, vi } from "bun:test";
 import { initTheme } from "@oh-my-pi/pi-coding-agent/modes/theme/theme";
+import type { InteractiveModeContext } from "@oh-my-pi/pi-coding-agent/modes/types";
 import { UiHelpers } from "@oh-my-pi/pi-coding-agent/modes/utils/ui-helpers";
 import { Container } from "@oh-my-pi/pi-tui";
 
@@ -16,13 +17,13 @@ describe("InteractiveMode.showStatus", () => {
 	});
 
 	test("coalesces immediately-sequential status messages", () => {
-		const ctx: any = {
+		const ctx = {
 			chatContainer: new Container(),
 			ui: { requestRender: vi.fn() },
 			isBackgrounded: false,
 			lastStatusSpacer: undefined,
 			lastStatusText: undefined,
-		};
+		} as unknown as InteractiveModeContext;
 		const helpers = new UiHelpers(ctx);
 
 		helpers.showStatus("STATUS_ONE");
@@ -37,13 +38,13 @@ describe("InteractiveMode.showStatus", () => {
 	});
 
 	test("appends a new status line if something else was added in between", () => {
-		const ctx: any = {
+		const ctx = {
 			chatContainer: new Container(),
 			ui: { requestRender: vi.fn() },
 			isBackgrounded: false,
 			lastStatusSpacer: undefined,
 			lastStatusText: undefined,
-		};
+		} as unknown as InteractiveModeContext;
 		const helpers = new UiHelpers(ctx);
 
 		helpers.showStatus("STATUS_ONE");
@@ -58,4 +59,18 @@ describe("InteractiveMode.showStatus", () => {
 		expect(ctx.chatContainer.children).toHaveLength(5);
 		expect(renderLastLine(ctx.chatContainer)).toContain("STATUS_TWO");
 	});
+
+	test("clears stale optimistic user signatures when rebuilding transcript state", () => {
+		const ctx = {
+			chatContainer: new Container(),
+			pendingTools: new Map(),
+			ui: { requestRender: vi.fn() },
+			optimisticUserMessageSignature: "hello\u00001",
+		} as unknown as InteractiveModeContext;
+		const helpers = new UiHelpers(ctx);
+
+		helpers.renderSessionContext({ messages: [], entries: [] });
+
+		expect(ctx.optimisticUserMessageSignature).toBeUndefined();
+	});
 });