diff --git a/src/tui/tui-input-history.test.ts b/src/tui/tui-input-history.test.ts
new file mode 100644
index 000000000..1a6870b99
--- /dev/null
+++ b/src/tui/tui-input-history.test.ts
@@ -0,0 +1,99 @@
+import { describe, expect, it, vi } from "vitest";
+
+import { createEditorSubmitHandler } from "./tui.js";
+
+describe("createEditorSubmitHandler", () => {
+  it("adds submitted messages to editor history", () => {
+    const editor = {
+      setText: vi.fn(),
+      addToHistory: vi.fn(),
+    };
+
+    const handler = createEditorSubmitHandler({
+      editor,
+      handleCommand: vi.fn(),
+      sendMessage: vi.fn(),
+    });
+
+    handler("hello world");
+
+    expect(editor.setText).toHaveBeenCalledWith("");
+    expect(editor.addToHistory).toHaveBeenCalledWith("hello world");
+  });
+
+  it("trims input before adding to history", () => {
+    const editor = {
+      setText: vi.fn(),
+      addToHistory: vi.fn(),
+    };
+
+    const handler = createEditorSubmitHandler({
+      editor,
+      handleCommand: vi.fn(),
+      sendMessage: vi.fn(),
+    });
+
+    handler("   hi   ");
+
+    expect(editor.addToHistory).toHaveBeenCalledWith("hi");
+  });
+
+  it("does not add empty submissions to history", () => {
+    const editor = {
+      setText: vi.fn(),
+      addToHistory: vi.fn(),
+    };
+
+    const handler = createEditorSubmitHandler({
+      editor,
+      handleCommand: vi.fn(),
+      sendMessage: vi.fn(),
+    });
+
+    handler("   ");
+
+    expect(editor.addToHistory).not.toHaveBeenCalled();
+  });
+
+  it("routes slash commands to handleCommand", () => {
+    const editor = {
+      setText: vi.fn(),
+      addToHistory: vi.fn(),
+    };
+    const handleCommand = vi.fn();
+    const sendMessage = vi.fn();
+
+    const handler = createEditorSubmitHandler({
+      editor,
+      handleCommand,
+      sendMessage,
+    });
+
+    handler("/models");
+
+    expect(editor.addToHistory).toHaveBeenCalledWith("/models");
+    expect(handleCommand).toHaveBeenCalledWith("/models");
+    expect(sendMessage).not.toHaveBeenCalled();
+  });
+
+  it("routes normal messages to sendMessage", () => {
+    const editor = {
+      setText: vi.fn(),
+      addToHistory: vi.fn(),
+    };
+    const handleCommand = vi.fn();
+    const sendMessage = vi.fn();
+
+    const handler = createEditorSubmitHandler({
+      editor,
+      handleCommand,
+      sendMessage,
+    });
+
+    handler("hello");
+
+    expect(editor.addToHistory).toHaveBeenCalledWith("hello");
+    expect(sendMessage).toHaveBeenCalledWith("hello");
+    expect(handleCommand).not.toHaveBeenCalled();
+  });
+});
diff --git a/src/tui/tui.ts b/src/tui/tui.ts
index a5e6e34d7..bf777f133 100644
--- a/src/tui/tui.ts
+++ b/src/tui/tui.ts
@@ -36,6 +36,30 @@ import type {
 export { resolveFinalAssistantText } from "./tui-formatters.js";
 export type { TuiOptions } from "./tui-types.js";
 
+export function createEditorSubmitHandler(params: {
+  editor: {
+    setText: (value: string) => void;
+    addToHistory: (value: string) => void;
+  };
+  handleCommand: (value: string) => Promise<void> | void;
+  sendMessage: (value: string) => Promise<void> | void;
+}) {
+  return (text: string) => {
+    const value = text.trim();
+    params.editor.setText("");
+    if (!value) return;
+
+    // Enable built-in editor prompt history navigation (up/down).
+    params.editor.addToHistory(value);
+
+    if (value.startsWith("/")) {
+      void params.handleCommand(value);
+      return;
+    }
+    void params.sendMessage(value);
+  };
+}
+
 export async function runTui(opts: TuiOptions) {
   const config = loadConfig();
   const initialSessionInput = (opts.session ?? "").trim();
@@ -473,16 +497,11 @@ export async function runTui(opts: TuiOptions) {
     });
 
   updateAutocompleteProvider();
-  editor.onSubmit = (text) => {
-    const value = text.trim();
-    editor.setText("");
-    if (!value) return;
-    if (value.startsWith("/")) {
-      void handleCommand(value);
-      return;
-    }
-    void sendMessage(value);
-  };
+  editor.onSubmit = createEditorSubmitHandler({
+    editor,
+    handleCommand,
+    sendMessage,
+  });
 
   editor.onEscape = () => {
     void abortActive();