v0.5: TCP STT client with PTT on/off, server endpoint in config + UI

Robovoice.App/AppConfig.cs

@@ -12,6 +12,7 @@ public sealed class AppConfig
     public int LengthScale { get; set; } = 100;
     public int NoiseWScale { get; set; } = 800;
     public bool MinimizeToTray { get; set; } = true;
+    public string ServerEndpoint { get; set; } = "127.0.0.1:5210";
 
     public static string AppDataDir => Path.Combine(
         Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData),

Robovoice.App/MainForm.Designer.cs

@@ -16,6 +16,9 @@ partial class MainForm
     private Label lblFile = null!;
     private Button btnBrowseFile = null!;
     private Label lblFileName = null!;
+    private Label lblServer = null!;
+    private TextBox txtServer = null!;
+    private Button btnConnect = null!;
     private Label lblLineStatus = null!;
     private RichTextBox txtLog = null!;
     private CheckBox chkMinimizeToTray = null!;
@@ -54,6 +57,9 @@ partial class MainForm
         lblFile = new Label();
         btnBrowseFile = new Button();
         lblFileName = new Label();
+        lblServer = new Label();
+        txtServer = new TextBox();
+        btnConnect = new Button();
         lblLineStatus = new Label();
         txtLog = new RichTextBox();
         chkMinimizeToTray = new CheckBox();
@@ -134,13 +140,29 @@ partial class MainForm
         // lblFileName
         lblFileName.Text = "(none)";
         lblFileName.Location = new Point(155, 48);
-        lblFileName.Size = new Size(490, 23);
+        lblFileName.Size = new Size(280, 23);
         lblFileName.TextAlign = ContentAlignment.MiddleLeft;
         lblFileName.ForeColor = Color.Gray;
 
+        // lblServer
+        lblServer.Text = "Server:";
+        lblServer.Location = new Point(440, 48);
+        lblServer.Size = new Size(45, 23);
+        lblServer.TextAlign = ContentAlignment.MiddleLeft;
+
+        // txtServer
+        txtServer.Location = new Point(488, 45);
+        txtServer.Size = new Size(110, 23);
+
+        // btnConnect
+        btnConnect.Text = "Connect";
+        btnConnect.Location = new Point(603, 44);
+        btnConnect.Size = new Size(60, 25);
+        btnConnect.UseVisualStyleBackColor = true;
+
         // lblLineStatus
         lblLineStatus.Text = "";
-        lblLineStatus.Location = new Point(650, 48);
+        lblLineStatus.Location = new Point(645, 48);
         lblLineStatus.Size = new Size(160, 23);
         lblLineStatus.TextAlign = ContentAlignment.MiddleRight;
         lblLineStatus.ForeColor = Color.DarkBlue;
@@ -254,6 +276,9 @@ partial class MainForm
         Controls.Add(lblFile);
         Controls.Add(btnBrowseFile);
         Controls.Add(lblFileName);
+        Controls.Add(lblServer);
+        Controls.Add(txtServer);
+        Controls.Add(btnConnect);
         Controls.Add(lblLineStatus);
         Controls.Add(lblNoise);
         Controls.Add(trkNoise);

Robovoice.App/MainForm.cs

@@ -2,7 +2,7 @@ using NAudio.Wave;
 using Robovoice.App;
 using Robovoice.Core;
 using Robovoice.Core.Voices;
-using Robovoice.Stt.File;
+using Robovoice.Stt.Tcp;
 using Robovoice.Tts.LibPiper;
 using System.Diagnostics;
 
@@ -16,7 +16,7 @@ internal sealed partial class MainForm : Form
 
     private LibPiperTtsEngine? _tts;
     private AudioOutput? _audioOutput;
-    private FileSttSource? _sttSource;
+    private TcpSttSource? _sttSource;
     private Orchestrator? _orchestrator;
     private PttHotkey? _pttHotkey;
     private NotifyIcon? _trayIcon;
@@ -61,6 +61,7 @@ internal sealed partial class MainForm : Form
         OnSliderScroll(null, EventArgs.Empty);
 
         chkMinimizeToTray.Checked = _config.MinimizeToTray;
+        txtServer.Text = _config.ServerEndpoint;
 
         btnBrowseFile.Click += OnBrowseFile;
         btnTestVoice.Click += OnTestVoice;
@@ -70,6 +71,8 @@ internal sealed partial class MainForm : Form
         txtPttKey.KeyDown += OnPttKeyDown;
         cmbOutput.SelectedIndexChanged += OnOutputChanged;
         cmbVoice.SelectedIndexChanged += OnVoiceChanged;
+        txtServer.Leave += OnServerChanged;
+        btnConnect.Click += OnConnect;
 
         trkNoise.Scroll += OnSliderScroll;
         trkSpeed.Scroll += OnSliderScroll;
@@ -239,7 +242,13 @@ internal sealed partial class MainForm : Form
             lengthScale: trkSpeed.Value / 100.0f,
             noiseWScale: trkNoiseW.Value / 1000.0f);
         _audioOutput = new AudioOutput();
-        _sttSource = new FileSttSource();
+
+        if (_sttSource is null)
+        {
+            _sttSource = new TcpSttSource { ServerEndpoint = txtServer.Text, Log = Log };
+            Log($"STT endpoint: {_sttSource.ServerEndpoint} (press Connect)");
+        }
+
         _orchestrator?.DisposeAsync().AsTask().Wait();
         _orchestrator = new Orchestrator(_tts, _audioOutput, _sttSource, Log)
         {
@@ -249,7 +258,7 @@ internal sealed partial class MainForm : Form
         try
         {
             await _orchestrator.InitializeTtsAsync();
-            Log("Engine ready. Select a text file and press PTT key.");
+            Log("Engine ready. Press PTT to send to STT server.");
             SetupHotkey();
         }
         catch (Exception ex)
@@ -271,22 +280,27 @@ internal sealed partial class MainForm : Form
     private void OnPttPressed(object? sender, EventArgs e)
     {
         Log("PTT pressed");
+        try
+        {
+            _sttSource?.SendOn();
+        }
+        catch (Exception ex)
+        {
+            Log($"SendOn failed: {ex.Message}");
+        }
     }
 
     private void OnPttReleased(object? sender, EventArgs e)
     {
         Log("PTT released");
-        if (_orchestrator is null || _sttSource is null) return;
+        try
-
-        if (_sttSource.LineCount == 0)
         {
-            Log("No text file loaded.");
+            _sttSource?.SendOff();
-            return;
+        }
+        catch (Exception ex)
+        {
+            Log($"SendOff failed: {ex.Message}");
         }
-
-        UpdateLineStatus();
-        _orchestrator.TriggerNextLine();
-        UpdateLineStatus();
     }
 
     private void OnBrowseFile(object? sender, EventArgs e)
@@ -294,16 +308,16 @@ internal sealed partial class MainForm : Form
         using var dlg = new OpenFileDialog
         {
             Filter = "Text files (*.txt)|*.txt|All files (*.*)|*.*",
-            Title = "Select a text file to read sequentially",
+            Title = "Select a text file to speak",
         };
 
         if (dlg.ShowDialog() == DialogResult.OK)
         {
-            _sttSource?.LoadFile(dlg.FileName);
+            string text = File.ReadAllText(dlg.FileName);
             lblFileName.Text = Path.GetFileName(dlg.FileName);
             lblFileName.ForeColor = Color.Black;
-            UpdateLineStatus();
+            Log($"Loaded: {dlg.FileName} ({text.Length} chars)");
-            Log($"Loaded: {dlg.FileName} ({_sttSource?.LineCount} lines)");
+            _ = _orchestrator?.SynthesizeAsync(text);
         }
     }
 
@@ -411,15 +425,38 @@ internal sealed partial class MainForm : Form
         SaveConfig();
     }
 
-    private void UpdateLineStatus()
+    private void OnServerChanged(object? sender, EventArgs e)
     {
-        if (_sttSource is null || _sttSource.LineCount == 0)
+        if (_sttSource is not null)
         {
-            lblLineStatus.Text = "";
+            _sttSource.ServerEndpoint = txtServer.Text;
+            Log($"Server endpoint: {txtServer.Text}");
+        }
+        SaveConfig();
+    }
+
+    private async void OnConnect(object? sender, EventArgs e)
+    {
+        if (_sttSource is null)
+        {
+            Log("STT source not initialized.");
             return;
         }
-        int displayIdx = (_sttSource.CurrentIndex % _sttSource.LineCount) + 1;
+
-        lblLineStatus.Text = $"Line {displayIdx}/{_sttSource.LineCount}";
+        _sttSource.ServerEndpoint = txtServer.Text;
+        SaveConfig();
+        btnConnect.Enabled = false;
+        try
+        {
+            if (_sttSource.IsRunning)
+                await _sttSource.ReconnectAsync();
+            else
+                await _sttSource.StartAsync();
+        }
+        finally
+        {
+            btnConnect.Enabled = true;
+        }
     }
 
     private void SetupTray()
@@ -487,6 +524,7 @@ internal sealed partial class MainForm : Form
         _config.LengthScale = trkSpeed.Value;
         _config.NoiseWScale = trkNoiseW.Value;
         _config.MinimizeToTray = chkMinimizeToTray.Checked;
+        _config.ServerEndpoint = txtServer.Text;
         _config.Save();
     }
 
@@ -508,7 +546,8 @@ internal sealed partial class MainForm : Form
     {
         _pttHotkey?.Dispose();
         _trayIcon!.Visible = false;
-        _orchestrator?.DisposeAsync().AsTask().Wait();
+        _orchestrator?.DisposeAsync().AsTask().Wait(2000);
+        _sttSource?.DisposeAsync().AsTask().Wait(2000);
         SaveConfig();
     }
 }

Robovoice.App/Orchestrator.cs

@@ -1,5 +1,4 @@
 using Robovoice.Core;
-using Robovoice.Stt.File;
 using Robovoice.Tts.LibPiper;
 
 namespace Robovoice.App;
@@ -8,7 +7,7 @@ internal sealed class Orchestrator : IAsyncDisposable
 {
     private readonly LibPiperTtsEngine _tts;
     private readonly AudioOutput _audioOutput;
-    private readonly FileSttSource _sttSource;
+    private readonly ISttSource _sttSource;
     private readonly Action<string> _log;
     private CancellationTokenSource? _currentCts;
     private bool _disposed;
@@ -18,7 +17,7 @@ internal sealed class Orchestrator : IAsyncDisposable
     public Orchestrator(
         LibPiperTtsEngine tts,
         AudioOutput audioOutput,
-        FileSttSource sttSource,
+        ISttSource sttSource,
         Action<string> log)
     {
         _tts = tts;
@@ -97,15 +96,6 @@ internal sealed class Orchestrator : IAsyncDisposable
         sw.Stop();
     }
 
-    public void TriggerNextLine()
-    {
-        _sttSource.EmitNext();
-    }
-
-    public string? GetPendingLine() => _sttSource.GetPendingLine();
-    public int GetCurrentLineIndex() => _sttSource.CurrentIndex;
-    public int GetLineCount() => _sttSource.LineCount;
-
     public async ValueTask DisposeAsync()
     {
         if (_disposed) return;

Robovoice.App/Robovoice.App.csproj

@@ -3,8 +3,7 @@
   <ItemGroup>
     <ProjectReference Include="..\Robovoice.Core\Robovoice.Core.csproj" />
     <ProjectReference Include="..\Robovoice.Tts.LibPiper\Robovoice.Tts.LibPiper.csproj" />
-    <ProjectReference Include="..\Robovoice.Stt.File\Robovoice.Stt.File.csproj" />
+    <ProjectReference Include="..\Robovoice.Stt.Tcp\Robovoice.Stt.Tcp.csproj" />
-    <ProjectReference Include="..\Robovoice.Stt.Udp\Robovoice.Stt.Udp.csproj" />
   </ItemGroup>
 
   <ItemGroup>

Robovoice.Core/ISttSource.cs

@@ -2,6 +2,8 @@ namespace Robovoice.Core;
 
 public interface ISttSource : IAsyncDisposable
 {
+    event TranscriptEventHandler? TranscriptReceived;
+
     Task StartAsync(CancellationToken ct = default);
 
     Task StopAsync(CancellationToken ct = default);

Robovoice.Stt.Tcp/Robovoice.Stt.Tcp.csproj

@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
 
   <ItemGroup>
     <ProjectReference Include="..\Robovoice.Core\Robovoice.Core.csproj" />

Robovoice.Stt.Tcp/TcpSttSource.cs

@@ -0,0 +1,253 @@
+using System.Net;
+using System.Net.Sockets;
+using System.Text.Json;
+using System.Text.Json.Serialization;
+using Robovoice.Core;
+
+namespace Robovoice.Stt.Tcp;
+
+public sealed class TcpSttSource : ISttSource
+{
+    private TcpClient? _tcp;
+    private NetworkStream? _stream;
+    private StreamReader? _reader;
+    private StreamWriter? _writer;
+    private CancellationTokenSource? _cts;
+    private Task? _runTask;
+    private readonly object _sendLock = new();
+    private bool _disposed;
+
+    public string ServerEndpoint { get; set; } = "127.0.0.1:5210";
+
+    public bool IsRunning => _cts is not null;
+
+    public Action<string>? Log { get; set; }
+
+    public event TranscriptEventHandler? TranscriptReceived;
+
+    public Task StartAsync(CancellationToken ct = default)
+    {
+        ObjectDisposedException.ThrowIf(_disposed, this);
+        if (_cts is not null)
+            return Task.CompletedTask;
+
+        _cts = CancellationTokenSource.CreateLinkedTokenSource(ct);
+        _runTask = RunAsync(_cts.Token);
+        return Task.CompletedTask;
+    }
+
+    public async Task StopAsync(CancellationToken ct = default)
+    {
+        if (_cts is not null)
+            _cts.Cancel();
+
+        CleanupConnection();
+
+        if (_runTask is not null)
+        {
+            try { await _runTask.WaitAsync(ct); }
+            catch { }
+            _runTask = null;
+        }
+
+        _cts?.Dispose();
+        _cts = null;
+    }
+
+    private async Task RunAsync(CancellationToken ct)
+    {
+        while (!ct.IsCancellationRequested)
+        {
+            IPEndPoint? endpoint = ParseEndpoint(ServerEndpoint);
+            if (endpoint is null)
+            {
+                Log?.Invoke($"STT: invalid endpoint '{ServerEndpoint}'");
+                try { await Task.Delay(3000, ct); } catch { break; }
+                continue;
+            }
+
+            try
+            {
+                _tcp = new TcpClient();
+                using var connectCts = CancellationTokenSource.CreateLinkedTokenSource(ct);
+                connectCts.CancelAfter(TimeSpan.FromSeconds(5));
+                await _tcp.ConnectAsync(endpoint.Address, endpoint.Port, connectCts.Token);
+
+                _stream = _tcp.GetStream();
+                _reader = new StreamReader(_stream, System.Text.Encoding.UTF8);
+                _writer = new StreamWriter(_stream, System.Text.Encoding.UTF8) { AutoFlush = true };
+
+                Log?.Invoke($"STT: connected to {ServerEndpoint}");
+
+                await ReceiveLoopAsync(ct);
+            }
+            catch (OperationCanceledException)
+            {
+                break;
+            }
+            catch (Exception ex)
+            {
+                Log?.Invoke($"STT: connection failed ({ex.Message}), retrying...");
+            }
+            finally
+            {
+                CleanupConnection();
+            }
+
+            if (!ct.IsCancellationRequested)
+            {
+                try { await Task.Delay(3000, ct); }
+                catch (OperationCanceledException) { break; }
+            }
+        }
+    }
+
+    private async Task ReceiveLoopAsync(CancellationToken ct)
+    {
+        while (!ct.IsCancellationRequested && _reader is not null)
+        {
+            string? line;
+            try
+            {
+                line = await _reader.ReadLineAsync(ct);
+            }
+            catch
+            {
+                break;
+            }
+
+            if (line is null)
+                break;
+
+            TranscriptMessage? message = ParseTranscriptLine(line);
+            if (message is null)
+                continue;
+
+            TranscriptReceived?.Invoke(this, new TranscriptEventArgs
+            {
+                Message = message,
+            });
+        }
+    }
+
+    public void SendOn()
+    {
+        SendControl("on");
+    }
+
+    public void SendOff()
+    {
+        SendControl("off");
+    }
+
+    public async Task ReconnectAsync(CancellationToken ct = default)
+    {
+        if (_cts is null)
+            return;
+
+        Log?.Invoke("STT: reconnecting...");
+        CleanupConnection();
+
+        try { await Task.Delay(500, ct); }
+        catch (OperationCanceledException) { return; }
+    }
+
+    private void SendControl(string evt)
+    {
+        lock (_sendLock)
+        {
+            if (_writer is null)
+                return;
+
+            try
+            {
+                _writer.WriteLine(JsonSerializer.Serialize(new ControlDto { Event = evt }));
+            }
+            catch
+            {
+                Log?.Invoke($"STT: failed to send '{evt}' (not connected?)");
+            }
+        }
+    }
+
+    private void CleanupConnection()
+    {
+        lock (_sendLock)
+        {
+            _writer?.Dispose();
+            _reader?.Dispose();
+            _stream?.Dispose();
+            _tcp?.Dispose();
+            _writer = null;
+            _reader = null;
+            _stream = null;
+            _tcp = null;
+        }
+    }
+
+    private static IPEndPoint? ParseEndpoint(string endpoint)
+    {
+        int colon = endpoint.LastIndexOf(':');
+        if (colon <= 0)
+            return null;
+
+        string host = endpoint[..colon];
+        if (!int.TryParse(endpoint[(colon + 1)..], out int port))
+            return null;
+
+        if (IPAddress.TryParse(host, out var addr))
+            return new IPEndPoint(addr, port);
+
+        try
+        {
+            var addresses = Dns.GetHostAddresses(host);
+            addr = addresses.FirstOrDefault(a => a.AddressFamily == AddressFamily.InterNetwork);
+            if (addr is null)
+                return null;
+            return new IPEndPoint(addr, port);
+        }
+        catch
+        {
+            return null;
+        }
+    }
+
+    private static TranscriptMessage? ParseTranscriptLine(string line)
+    {
+        if (string.IsNullOrWhiteSpace(line))
+            return null;
+
+        try
+        {
+            var dto = JsonSerializer.Deserialize<TransmitDto>(line);
+            if (dto is null)
+                return null;
+
+            var type = dto.Final ? TranscriptType.Final : TranscriptType.Partial;
+            return new TranscriptMessage(type, dto.Text ?? string.Empty);
+        }
+        catch (JsonException)
+        {
+            return null;
+        }
+    }
+
+    public async ValueTask DisposeAsync()
+    {
+        if (_disposed) return;
+        await StopAsync();
+        _disposed = true;
+    }
+}
+
+internal sealed class ControlDto
+{
+    [JsonPropertyName("event")]
+    public string Event { get; set; } = string.Empty;
+}
+
+internal sealed class TransmitDto
+{
+    public bool Final { get; set; }
+    public string Text { get; set; } = string.Empty;
+}

Robovoice.slnx

@@ -2,6 +2,6 @@
   <Project Path="Robovoice.App/Robovoice.App.csproj" />
   <Project Path="Robovoice.Core/Robovoice.Core.csproj" />
   <Project Path="Robovoice.Stt.File/Robovoice.Stt.File.csproj" />
-  <Project Path="Robovoice.Stt.Udp/Robovoice.Stt.Udp.csproj" />
+  <Project Path="Robovoice.Stt.Tcp/Robovoice.Stt.Tcp.csproj" />
   <Project Path="Robovoice.Tts.LibPiper/Robovoice.Tts.LibPiper.csproj" />
 </Solution>

Server/NOTES.md

@@ -0,0 +1,264 @@
+# Server implementation notes
+
+The STT server listens for TCP connections from Robovoice, captures audio
+from a microphone when `on` is received, runs speech recognition (Moonshine),
+and sends transcript messages back over the same connection.
+
+## Architecture
+
+```
+                         ┌── on/off (TCP, newline-delimited JSON)
+Robovoice  ──────────────►│
+                         │  STT Server
+Robovoice  ◄──────────────┤
+                         └── partial/final (TCP, newline-delimited JSON)
+```
+
+The server:
+1. Listens on a TCP port (e.g. 5210)
+2. Accepts a connection from Robovoice
+3. Reads lines: waits for `{"event":"on"}`
+4. Records audio from the microphone
+5. Waits for `{"event":"off"}` (or a timeout)
+6. Runs STT on the captured audio
+7. Sends `{"final":true,"text":"..."}`\n back over the connection
+
+## Framing
+
+Every message is a single JSON object on one line, terminated by `\n`. No
+length prefix, no binary framing. Use `readline()` / `StreamReader.ReadLineAsync()`.
+
+## Python server with Moonshine
+
+[Moonshine](https://github.com/usefulsensors/moonshine) is a lightweight ASR
+model by Useful Sensors. Install with `pip install moonshine`.
+
+```python
+import socket
+import json
+import numpy as np
+import sounddevice as sd
+import moonshine
+
+LISTEN_PORT = 5210
+SAMPLE_RATE = 16000
+
+model = moonshine.MoonshineModel(model="moonshine/base")
+
+server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+server.bind(("0.0.0.0", LISTEN_PORT))
+server.listen(1)
+
+print(f"STT server listening on :{LISTEN_PORT}")
+
+while True:
+    conn, addr = server.accept()
+    print(f"Client connected: {addr}")
+
+    buf = ""
+    with conn:
+        while True:
+            data = conn.recv(4096).decode("utf-8")
+            if not data:
+                break
+            buf += data
+
+            while "\n" in buf:
+                line, buf = buf.split("\n", 1)
+                msg = json.loads(line)
+
+                if msg.get("event") == "on":
+                    print("PTT on — recording")
+                    audio_chunks = []
+
+                    # Record until "off" or timeout
+                    conn.settimeout(0.1)
+                    while True:
+                        try:
+                            data2 = conn.recv(4096).decode("utf-8")
+                            if not data2:
+                                break
+                            buf += data2
+                            while "\n" in buf:
+                                line2, buf = buf.split("\n", 1)
+                                msg2 = json.loads(line2)
+                                if msg2.get("event") == "off":
+                                    break
+                        except socket.timeout:
+                            pass
+
+                        chunk = sd.rec(int(SAMPLE_RATE * 0.1),
+                                      samplerate=SAMPLE_RATE,
+                                      channels=1, dtype="float32")
+                        sd.wait()
+                        audio_chunks.append(chunk.flatten())
+
+                    conn.settimeout(None)
+
+                    if not audio_chunks:
+                        continue
+
+                    audio = np.concatenate(audio_chunks)
+                    print(f"Captured {len(audio)/SAMPLE_RATE:.1f}s")
+
+                    text = moonshine.transcribe(model, audio).strip()
+
+                    if text:
+                        print(f"Transcript: {text}")
+                        reply = json.dumps({"final": True, "text": text})
+                        conn.sendall((reply + "\n").encode("utf-8"))
+                    else:
+                        print("Empty transcript")
+```
+
+## Python server with streaming partials
+
+For lower latency, send partial results while still recording:
+
+```python
+import socket
+import json
+import numpy as np
+import sounddevice as sd
+import moonshine
+
+LISTEN_PORT = 5210
+SAMPLE_RATE = 16000
+CHUNK_DURATION = 0.5
+
+model = moonshine.MoonshineModel(model="moonshine/base")
+
+server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+server.bind(("0.0.0.0", LISTEN_PORT))
+server.listen(1)
+
+print(f"STT server listening on :{LISTEN_PORT}")
+
+while True:
+    conn, addr = server.accept()
+    print(f"Client connected: {addr}")
+    buf = ""
+
+    with conn:
+        while True:
+            data = conn.recv(4096).decode("utf-8")
+            if not data:
+                break
+            buf += data
+
+            while "\n" in buf:
+                line, buf = buf.split("\n", 1)
+                msg = json.loads(line)
+
+                if msg.get("event") != "on":
+                    continue
+
+                print("PTT on — recording")
+                audio_chunks = []
+
+                while True:
+                    try:
+                        conn.settimeout(CHUNK_DURATION)
+                        data2 = conn.recv(4096).decode("utf-8")
+                        if not data2:
+                            break
+                        buf += data2
+                        while "\n" in buf:
+                            line2, buf = buf.split("\n", 1)
+                            msg2 = json.loads(line2)
+                            if msg2.get("event") == "off":
+                                break
+                    except socket.timeout:
+                        pass
+
+                    chunk = sd.rec(int(SAMPLE_RATE * CHUNK_DURATION),
+                                  samplerate=SAMPLE_RATE,
+                                  channels=1, dtype="float32")
+                    sd.wait()
+                    audio_chunks.append(chunk.flatten())
+
+                    # Send partial every few chunks
+                    if len(audio_chunks) % 4 == 0:
+                        partial_audio = np.concatenate(audio_chunks)
+                        partial_text = moonshine.transcribe(model, partial_audio).strip()
+                        if partial_text:
+                            reply = json.dumps({"final": False, "text": partial_text})
+                            conn.sendall((reply + "\n").encode("utf-8"))
+
+                conn.settimeout(None)
+
+                if not audio_chunks:
+                    continue
+
+                audio = np.concatenate(audio_chunks)
+                text = moonshine.transcribe(model, audio).strip()
+
+                if text:
+                    print(f"Final: {text}")
+                    reply = json.dumps({"final": True, "text": text})
+                    conn.sendall((reply + "\n").encode("utf-8"))
+```
+
+## C# server skeleton
+
+```csharp
+using System.Net;
+using System.Net.Sockets;
+using System.Text.Json;
+
+var listener = new TcpListener(IPAddress.Any, 5210);
+listener.Start();
+
+Console.WriteLine("STT server listening on :5210");
+
+while (true)
+{
+    var client = listener.AcceptTcpClient();
+    Console.WriteLine($"Client connected: {client.Client.RemoteEndPoint}");
+
+    using var stream = client.GetStream();
+    using var reader = new StreamReader(stream, Encoding.UTF8);
+    using var writer = new StreamWriter(stream, Encoding.UTF8) { AutoFlush = true };
+
+    string? line;
+    while ((line = reader.ReadLine()) is not null)
+    {
+        var msg = JsonSerializer.Deserialize<Dictionary<string, string>>(line);
+        if (msg?["event"] != "on")
+            continue;
+
+        Console.WriteLine("PTT on — recording");
+        // Capture audio...
+
+        // Read until "off"
+        while ((line = reader.ReadLine()) is not null)
+        {
+            msg = JsonSerializer.Deserialize<Dictionary<string, string>>(line);
+            if (msg?["event"] == "off")
+                break;
+        }
+
+        // Run STT...
+        string text = "recognized text here";
+
+        var reply = JsonSerializer.Serialize(new { final = true, text });
+        writer.WriteLine(reply);
+    }
+}
+```
+
+## Tips
+
+- **One connection per client:** Robovoice maintains a single persistent TCP
+  connection. The server should handle one client at a time (or track
+  multiple if needed).
+- **Timeout:** implement a recording timeout in case the `off` message is
+  delayed or the client disconnects. 10–30 seconds is reasonable.
+- **Partials:** optional but improve UX — Robovoice logs them so the user
+  sees live feedback. Only `final` triggers TTS.
+- **Encoding:** always UTF-8. Every line is a UTF-8 JSON object terminated
+  by `\n`.
+- **Reconnection:** Robovoice auto-reconnects every 3 seconds if the
+  connection drops. The server just needs to accept new connections.
+- **Moonshine models:** `moonshine/base` (faster, less accurate) or
+  `moonshine/tiny` (fastest). Choose based on your hardware.

Server/PROTOCOL.md

@@ -0,0 +1,70 @@
+# Robovoice TCP STT Protocol
+
+## Overview
+
+Robovoice acts as a **client**: it connects to a remote STT server over TCP,
+sends control messages when the user presses/releases the PTT key, and
+receives transcript messages back. The STT server captures audio from a
+microphone, runs speech recognition (Moonshine), and sends transcripts back
+over the same connection.
+
+```
+[Robovoice client] --TCP--> [STT server :5210]
+     │                            │
+     ├── {"event":"on"}\n  ──────►│
+     │                            ├── capture audio
+     ├── {"event":"off"}\n ──────►│
+     │                            ├── run STT
+     │◄── {"final":true,...}\n ──┤
+```
+
+## Transport
+
+- **Protocol:** TCP (reliable, ordered, connection-oriented)
+- **Server endpoint:** configurable in Robovoice UI (default `127.0.0.1:5210`)
+- **Framing:** newline-delimited JSON (NDJSON) — each message is a single
+  UTF-8 JSON object terminated by `\n`
+- **Auto-reconnect:** if the connection drops, Robovoice retries every 3
+  seconds until the server is available
+
+## Control messages (client → server)
+
+Sent by Robovoice when the user presses/releases the PTT key.
+
+```json
+{"event": "on"}
+```
+
+```json
+{"event": "off"}
+```
+
+| Field   | Type   | Description                        |
+|---------|--------|------------------------------------|
+| `event` | string | `"on"` (PTT pressed) or `"off"` (PTT released) |
+
+## Transcript messages (server → client)
+
+Sent by the server back to Robovoice over the same TCP connection.
+
+```json
+{"final": false, "text": "hello world"}
+```
+
+```json
+{"final": true, "text": "hello world how are you"}
+```
+
+| Field   | Type    | Required | Description                                      |
+|---------|---------|----------|--------------------------------------------------|
+| `final` | bool    | yes      | `true` = final result, `false` = partial         |
+| `text`  | string  | yes      | The transcript text (may be empty for partials)  |
+
+### Semantics
+
+- **`final: false`** — intermediate recognition result (partial). Robovoice
+  logs these but does not act on them (only `final` triggers TTS).
+- **`final: true`** — complete utterance. Robovoice feeds this to the TTS
+  engine and speaks it.
+
+Malformed JSON or unknown field values are silently dropped by the client.