diff --git a/src/AcDream.App/UI/UiChatInput.cs b/src/AcDream.App/UI/UiChatInput.cs
new file mode 100644
index 00000000..8bed6af0
--- /dev/null
+++ b/src/AcDream.App/UI/UiChatInput.cs
@@ -0,0 +1,158 @@
+using System;
+using System.Collections.Generic;
+using System.Numerics;
+
+namespace AcDream.App.UI;
+
+/// <summary>
+/// Editable one-line chat input. Port of retail <c>UIElement_Text</c> editable
+/// one-line mode + <c>ChatInterface</c>'s 100-entry command history. Caret is a
+/// glyph index; the caret pixel-X is Σ glyph advances (UiDatFont) to the caret.
+/// Submit (Enter / Send) fires <see cref="OnSubmit"/>, clears, and pushes history.
+/// Decomp: UIElement_Text MoveCursor @0x468d00, FindPixelsFromPos @0x472b40;
+/// ChatInterface ProcessCommand @0x4f5100 (history cap 100, sentinel 0xFFFFFFFF).
+/// </summary>
+public sealed class UiChatInput : UiElement
+{
+    public UiDatFont? DatFont { get; set; }
+    public AcDream.App.Rendering.BitmapFont? Font { get; set; }
+    public Vector4 TextColor { get; set; } = new(1f, 1f, 1f, 1f);
+    public Vector4 BackgroundColor { get; set; } = new(0f, 0f, 0f, 0.35f);
+    public float Padding { get; set; } = 4f;
+    public int MaxCharacters { get; set; } = 0xFFFF;
+
+    public Action<string>? OnSubmit { get; set; }
+
+    private string _text = "";
+    private int _caret;
+    public string Text => _text;
+    public int CaretPos => _caret;
+
+    private readonly List<string> _history = new();
+    private int _historyIndex = -1;
+    public int HistoryCount => _history.Count;
+
+    public UiChatInput()
+    {
+        AcceptsFocus = true;
+        IsEditControl = true;
+        CapturesPointerDrag = true;
+    }
+
+    public void InsertChar(char c)
+    {
+        if (c < 0x20 || c == 0x7F) return;
+        if (_text.Length >= MaxCharacters) return;
+        _text = _text.Insert(_caret, c.ToString());
+        _caret++;
+        _historyIndex = -1;
+    }
+
+    public void Backspace()
+    {
+        if (_caret == 0) return;
+        _text = _text.Remove(_caret - 1, 1);
+        _caret--;
+    }
+
+    public void DeleteForward()
+    {
+        if (_caret >= _text.Length) return;
+        _text = _text.Remove(_caret, 1);
+    }
+
+    public void MoveCaret(int delta) => _caret = Math.Clamp(_caret + delta, 0, _text.Length);
+    public void CaretHome() => _caret = 0;
+    public void CaretEnd() => _caret = _text.Length;
+
+    public void Submit()
+    {
+        var t = _text;
+        if (t.Trim().Length == 0) { Clear(); return; }
+        OnSubmit?.Invoke(t);
+        PushHistory(t);
+        Clear();
+    }
+
+    private void Clear() { _text = ""; _caret = 0; _historyIndex = -1; }
+
+    private void PushHistory(string t)
+    {
+        _history.Add(t);
+        if (_history.Count > 100) _history.RemoveAt(0);
+        _historyIndex = -1;
+    }
+
+    public void HistoryPrev()
+    {
+        if (_history.Count == 0) return;
+        _historyIndex = _historyIndex < 0 ? _history.Count - 1 : Math.Max(0, _historyIndex - 1);
+        SetTextFromHistory();
+    }
+
+    public void HistoryNext()
+    {
+        if (_historyIndex < 0) return;
+        _historyIndex++;
+        if (_historyIndex >= _history.Count) { _historyIndex = -1; Clear(); return; }
+        SetTextFromHistory();
+    }
+
+    private void SetTextFromHistory()
+    {
+        _text = _history[_historyIndex];
+        _caret = _text.Length;
+    }
+
+    public float CaretPixelX()
+        => DatFont is { } df ? df.MeasureWidth(_text.Substring(0, _caret))
+         : Font is { } bf ? bf.MeasureWidth(_text.Substring(0, _caret)) : 0f;
+
+    private bool _focused;
+
+    protected override void OnDraw(UiRenderContext ctx)
+    {
+        ctx.DrawRect(0, 0, Width, Height, BackgroundColor);
+        float lh = DatFont?.LineHeight ?? Font?.LineHeight ?? 14f;
+        float ty = (Height - lh) * 0.5f;
+        if (DatFont is { } df) ctx.DrawStringDat(df, _text, Padding, ty, TextColor);
+        else ctx.DrawString(_text, Padding, ty, TextColor, Font);
+
+        if (_focused)
+        {
+            float cx = Padding + CaretPixelX();
+            ctx.DrawRect(cx, ty, 1f, lh, TextColor);
+        }
+    }
+
+    public override bool OnEvent(in UiEvent e)
+    {
+        switch (e.Type)
+        {
+            case UiEventType.FocusGained: _focused = true; return true;
+            case UiEventType.FocusLost: _focused = false; _historyIndex = -1; return true;
+            case UiEventType.Char:
+                InsertChar((char)e.Data0);
+                return true;
+            case UiEventType.KeyDown:
+            {
+                var key = (Silk.NET.Input.Key)e.Data0;
+                switch (key)
+                {
+                    case Silk.NET.Input.Key.Enter:
+                    case Silk.NET.Input.Key.KeypadEnter: Submit(); return true;
+                    case Silk.NET.Input.Key.Backspace: Backspace(); return true;
+                    case Silk.NET.Input.Key.Delete: DeleteForward(); return true;
+                    case Silk.NET.Input.Key.Left: MoveCaret(-1); return true;
+                    case Silk.NET.Input.Key.Right: MoveCaret(1); return true;
+                    case Silk.NET.Input.Key.Home: CaretHome(); return true;
+                    case Silk.NET.Input.Key.End: CaretEnd(); return true;
+                    case Silk.NET.Input.Key.Up: HistoryPrev(); return true;
+                    case Silk.NET.Input.Key.Down: HistoryNext(); return true;
+                }
+                return false;
+            }
+        }
+        return false;
+    }
+}
diff --git a/tests/AcDream.App.Tests/UI/UiChatInputTests.cs b/tests/AcDream.App.Tests/UI/UiChatInputTests.cs
new file mode 100644
index 00000000..abbb751b
--- /dev/null
+++ b/tests/AcDream.App.Tests/UI/UiChatInputTests.cs
@@ -0,0 +1,72 @@
+using AcDream.App.UI;
+using Xunit;
+
+namespace AcDream.App.Tests.UI;
+
+public class UiChatInputTests
+{
+    [Fact]
+    public void InsertChar_AdvancesCaret()
+    {
+        var input = new UiChatInput();
+        input.InsertChar('h'); input.InsertChar('i');
+        Assert.Equal("hi", input.Text);
+        Assert.Equal(2, input.CaretPos);
+    }
+
+    [Fact]
+    public void Backspace_DeletesBeforeCaret()
+    {
+        var input = new UiChatInput();
+        foreach (var c in "abc") input.InsertChar(c);
+        input.MoveCaret(-1);
+        input.Backspace();
+        Assert.Equal("ac", input.Text);
+        Assert.Equal(1, input.CaretPos);
+    }
+
+    [Fact]
+    public void Submit_FiresCallback_ClearsText_PushesHistory()
+    {
+        string? sent = null;
+        var input = new UiChatInput { OnSubmit = t => sent = t };
+        foreach (var c in "hello") input.InsertChar(c);
+        input.Submit();
+        Assert.Equal("hello", sent);
+        Assert.Equal("", input.Text);
+        Assert.Equal(0, input.CaretPos);
+    }
+
+    [Fact]
+    public void EmptySubmit_DoesNotFire()
+    {
+        int n = 0;
+        var input = new UiChatInput { OnSubmit = _ => n++ };
+        input.Submit();
+        Assert.Equal(0, n);
+    }
+
+    [Fact]
+    public void History_UpDownBrowsesPreviousSubmissions()
+    {
+        var input = new UiChatInput { OnSubmit = _ => {} };
+        foreach (var c in "first") input.InsertChar(c); input.Submit();
+        foreach (var c in "second") input.InsertChar(c); input.Submit();
+        input.HistoryPrev();
+        Assert.Equal("second", input.Text);
+        input.HistoryPrev();
+        Assert.Equal("first", input.Text);
+        input.HistoryNext();
+        Assert.Equal("second", input.Text);
+        input.HistoryNext();
+        Assert.Equal("", input.Text);
+    }
+
+    [Fact]
+    public void History_CapsAt100()
+    {
+        var input = new UiChatInput { OnSubmit = _ => {} };
+        for (int i = 0; i < 150; i++) { input.InsertChar('x'); input.Submit(); }
+        Assert.True(input.HistoryCount <= 100);
+    }
+}