diff --git a/tests/AcDream.Headless.Tests/HeadlessConsoleTests.cs b/tests/AcDream.Headless.Tests/HeadlessConsoleTests.cs
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+++ b/tests/AcDream.Headless.Tests/HeadlessConsoleTests.cs
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+using System.Buffers.Binary;
+using System.Net;
+using System.Text;
+using AcDream.Core.Chat;
+using AcDream.Core.Net;
+using AcDream.Core.Net.Messages;
+using AcDream.Headless.Configuration;
+using AcDream.Headless.Credentials;
+using AcDream.Headless.Diagnostics;
+using AcDream.Headless.Hosting;
+using AcDream.Plugin.Abstractions;
+using AcDream.Runtime;
+using AcDream.Runtime.Chat;
+using AcDream.Runtime.Session;
+
+namespace AcDream.Headless.Tests;
+
+/// <summary>
+/// docs/plans/2026-09-07-headless-console.md — the headless interactive
+/// console. Two layers: <see cref="HeadlessConsoleInputReader"/> /
+/// <see cref="HeadlessConsoleController"/> tested in isolation (no live
+/// server, no <see cref="HeadlessSessionHost"/>), then
+/// <see cref="HeadlessSessionHost.SubmitConsoleLine"/> tested against a real
+/// host wired to <see cref="FixtureSessionOperations"/> — the same
+/// no-network fixture pattern <c>HeadlessSessionHostTests</c> already uses
+/// for <c>LoginCommandSequence</c>, proving the console reuses the EXACT
+/// same pipeline rather than a second parser.
+/// </summary>
+public sealed class HeadlessConsoleTests
+{
+    // ── HeadlessConsoleOptions (typed option resolution) ─────────────────
+
+    [Theory]
+    [InlineData(true, "0", false, true)]   // CLI flag always wins
+    [InlineData(false, "1", false, true)]  // env var wins over terminal default
+    [InlineData(false, "0", true, true)]   // env var "0" does not disable the terminal default
+    [InlineData(false, null, true, true)]  // no flag/env -> terminal-shaped default (on)
+    [InlineData(false, null, false, false)] // no flag/env -> terminal-shaped default (off)
+    public void ResolvePrefersFlagThenEnvironmentThenTerminalDefault(
+        bool commandLineFlag,
+        string? environmentValue,
+        bool standardInputIsTerminal,
+        bool expected)
+    {
+        bool resolved = HeadlessConsoleOptions.Resolve(
+            commandLineFlag,
+            _ => environmentValue,
+            standardInputIsTerminal);
+
+        Assert.Equal(expected, resolved);
+    }
+
+    [Fact]
+    public void CommandLineParsesTheBareConsoleFlag()
+    {
+        HeadlessCommandLine parsed = HeadlessCommandLine.Parse(
+            ["run", "--config", "bot.json", "--console"]);
+
+        Assert.True(parsed.Console);
+        Assert.Equal("bot.json", parsed.ConfigurationPath);
+    }
+
+    [Fact]
+    public void CommandLineWithoutTheFlagDefaultsConsoleOff()
+    {
+        HeadlessCommandLine parsed = HeadlessCommandLine.Parse(
+            ["run", "--config", "bot.json"]);
+
+        Assert.False(parsed.Console);
+    }
+
+    // ── HeadlessConsoleInputReader: reader-thread/ordering ───────────────
+
+    /// <summary>
+    /// The required reader-thread test: lines produced by the background
+    /// thread are drained, in FIFO order, entirely on the CALLING thread.
+    /// The reader thread itself never runs anything beyond
+    /// <c>ConcurrentQueue.Enqueue</c> — there is no dispatch code it could
+    /// execute — so this also structurally proves "never executed on the
+    /// reader thread," not just orders the output.
+    /// </summary>
+    [Fact]
+    public void LinesQueuedByTheReaderThreadDrainInOrderOnTheCallingThread()
+    {
+        using var input = new System.IO.StringReader(
+            "one" + Environment.NewLine
+            + "two" + Environment.NewLine
+            + "three" + Environment.NewLine);
+        using var reader = new HeadlessConsoleInputReader(input);
+
+        Assert.True(
+            reader.EndOfInput.Wait(TimeSpan.FromSeconds(5)),
+            "the reader thread never reached EOF");
+
+        int callingThread = Environment.CurrentManagedThreadId;
+        var drained = new List<string>();
+        while (reader.TryDequeue(out string line))
+        {
+            drained.Add(line);
+            // Proves the dequeue (and everything a caller does with the
+            // line) runs on THIS thread, not the reader thread.
+            Assert.Equal(callingThread, Environment.CurrentManagedThreadId);
+        }
+
+        Assert.Equal(["one", "two", "three"], drained);
+    }
+
+    // ── HeadlessConsoleController: /quit, /status, dispatch ordering ─────
+
+    [Fact]
+    public void ControllerDrainsEveryLineQueuedSinceTheLastTickInOrderOnOneCall()
+    {
+        // Simulates "input queued during a busy tick": every line is
+        // enqueued by the reader thread before DrainDue is ever called —
+        // one DrainDue call must still process all of them, in order.
+        using var input = new System.IO.StringReader(
+            "alpha" + Environment.NewLine
+            + "beta" + Environment.NewLine
+            + "gamma" + Environment.NewLine);
+        var handled = new List<string>();
+        using var quit = new CancellationTokenSource();
+        using var controller = new HeadlessConsoleController(
+            input,
+            TextWriter.Null,
+            line =>
+            {
+                handled.Add(line);
+                return SubmitOutcome.Sent;
+            },
+            () => string.Empty,
+            quit);
+
+        Assert.True(
+            WaitForEndOfInput(controller),
+            "the reader thread never reached EOF");
+        controller.DrainDue();
+
+        Assert.Equal(["alpha", "beta", "gamma"], handled);
+        Assert.Equal(3, controller.LastDrainCount);
+
+        // A second drain with nothing queued does nothing — proves DrainDue
+        // does not re-process already-handled lines.
+        controller.DrainDue();
+        Assert.Equal(["alpha", "beta", "gamma"], handled);
+        Assert.Equal(0, controller.LastDrainCount);
+    }
+
+    [Fact]
+    public void QuitRequestsCancellationAndNeverReachesSubmit()
+    {
+        using var input = new System.IO.StringReader("/quit" + Environment.NewLine);
+        var submitted = new List<string>();
+        var output = new StringWriter();
+        using var quit = new CancellationTokenSource();
+        using var controller = new HeadlessConsoleController(
+            input,
+            output,
+            line =>
+            {
+                submitted.Add(line);
+                return SubmitOutcome.Sent;
+            },
+            () => string.Empty,
+            quit);
+
+        Assert.True(WaitForEndOfInput(controller));
+        controller.DrainDue();
+
+        Assert.True(quit.IsCancellationRequested);
+        Assert.Empty(submitted);
+        Assert.Contains("quitting", output.ToString(), StringComparison.OrdinalIgnoreCase);
+    }
+
+    [Fact]
+    public void StatusPrintsTheProvidedStatusTextAndNeverReachesSubmit()
+    {
+        using var input = new System.IO.StringReader("/status" + Environment.NewLine);
+        var submitted = new List<string>();
+        var output = new StringWriter();
+        using var quit = new CancellationTokenSource();
+        using var controller = new HeadlessConsoleController(
+            input,
+            output,
+            line =>
+            {
+                submitted.Add(line);
+                return SubmitOutcome.Sent;
+            },
+            () => "generation=1 position=unknown plugins=0 loaded",
+            quit);
+
+        Assert.True(WaitForEndOfInput(controller));
+        controller.DrainDue();
+
+        Assert.Empty(submitted);
+        Assert.Contains(
+            "generation=1 position=unknown plugins=0 loaded",
+            output.ToString());
+    }
+
+    // ── HeadlessConsoleChatFormatter: channel-prefixed rendering ─────────
+
+    [Theory]
+    [InlineData("Bob", 0x50000010u, "hi", "[Local] Bob: hi")]
+    [InlineData("", 0u, "hi", "[Local] You: hi")]
+    public void FormatsLocalSpeechWithTheLocalLabel(
+        string sender, uint senderGuid, string text, string expected)
+    {
+        var entry = new RuntimeChatEntry(
+            Revision: 1,
+            SenderGuid: senderGuid,
+            Kind: (int)ChatKind.LocalSpeech,
+            Sender: sender,
+            Text: text,
+            ChannelName: string.Empty);
+
+        Assert.Equal(expected, HeadlessConsoleChatFormatter.Format(entry));
+    }
+
+    [Fact]
+    public void FormatsChannelBroadcastWithItsFriendlyName()
+    {
+        var entry = new RuntimeChatEntry(
+            Revision: 1,
+            SenderGuid: 0x50000010u,
+            Kind: (int)ChatKind.Channel,
+            Sender: "Bob",
+            Text: "group up",
+            ChannelName: "Fellowship");
+
+        Assert.Equal(
+            "[Fellowship] Bob: group up",
+            HeadlessConsoleChatFormatter.Format(entry));
+    }
+
+    [Theory]
+    [InlineData(0x50000010u, "Bob", "hi", "[Tell] Bob: hi")]
+    [InlineData(0u, "Bob", "hi", "[Tell] You -> Bob: hi")]
+    public void FormatsTellWithDirection(
+        uint senderGuid, string sender, string text, string expected)
+    {
+        var entry = new RuntimeChatEntry(
+            Revision: 1,
+            SenderGuid: senderGuid,
+            Kind: (int)ChatKind.Tell,
+            Sender: sender,
+            Text: text,
+            ChannelName: string.Empty);
+
+        Assert.Equal(expected, HeadlessConsoleChatFormatter.Format(entry));
+    }
+
+    // ── HeadlessSessionHost.SubmitConsoleLine: the real dispatch pipeline ─
+
+    [Fact]
+    public void SlashSayProducesTheSameOutboundTalkActionTheGraphicalRouteSends()
+    {
+        var captured = new List<byte[]>();
+        var operations = new FixtureSessionOperations
+        {
+            GameActionCapture = body => captured.Add(body),
+        };
+        using var credential = new HeadlessCredentialSecret("fixture", "password");
+        using var host = new HeadlessSessionHost(
+            Descriptor(),
+            credential,
+            new HeadlessDiagnosticWriter(TextWriter.Null),
+            operations);
+        Assert.Equal(
+            RuntimeSessionStartStatus.Connected,
+            host.Start().Status);
+
+        SubmitOutcome outcome = host.SubmitConsoleLine("/say hello", _ => { });
+
+        Assert.Equal(SubmitOutcome.Sent, outcome);
+        byte[] body = Assert.Single(captured);
+        Assert.Equal(ChatRequests.TalkOpcode, ActionOpcode(body));
+        Assert.Equal("hello", TalkText(body));
+    }
+
+    [Fact]
+    public void PlainTextProducesTheSameOutboundTalkActionAsSlashSay()
+    {
+        var captured = new List<byte[]>();
+        var operations = new FixtureSessionOperations
+        {
+            GameActionCapture = body => captured.Add(body),
+        };
+        using var credential = new HeadlessCredentialSecret("fixture", "password");
+        using var host = new HeadlessSessionHost(
+            Descriptor(),
+            credential,
+            new HeadlessDiagnosticWriter(TextWriter.Null),
+            operations);
+        Assert.Equal(
+            RuntimeSessionStartStatus.Connected,
+            host.Start().Status);
+
+        SubmitOutcome outcome = host.SubmitConsoleLine("hello", _ => { });
+
+        Assert.Equal(SubmitOutcome.Sent, outcome);
+        byte[] body = Assert.Single(captured);
+        Assert.Equal(ChatRequests.TalkOpcode, ActionOpcode(body));
+        Assert.Equal("hello", TalkText(body));
+    }
+
+    [Fact]
+    public void PluginVerbReachesTheRegisteredPluginCommandWithoutTouchingTheWire()
+    {
+        var captured = new List<byte[]>();
+        var operations = new FixtureSessionOperations
+        {
+            GameActionCapture = body => captured.Add(body),
+        };
+        using var credential = new HeadlessCredentialSecret("fixture", "password");
+        using var host = new HeadlessSessionHost(
+            Descriptor(),
+            credential,
+            new HeadlessDiagnosticWriter(TextWriter.Null),
+            operations);
+        Assert.Equal(
+            RuntimeSessionStartStatus.Connected,
+            host.Start().Status);
+        var received = new List<PluginCommand>();
+        using IDisposable registration = host.PluginCommands.Register(
+            "vt",
+            command => received.Add(command));
+
+        SubmitOutcome outcome = host.SubmitConsoleLine("/vt start", _ => { });
+
+        Assert.Equal(SubmitOutcome.ClientHandled, outcome);
+        PluginCommand command = Assert.Single(received);
+        Assert.Equal("vt", command.Verb);
+        Assert.Equal("start", command.Arguments);
+        Assert.Empty(captured);
+    }
+
+    [Fact]
+    public void UnknownVerbProducesTheSameInterfaceTextTheChatBoxShows()
+    {
+        var operations = new FixtureSessionOperations();
+        using var credential = new HeadlessCredentialSecret("fixture", "password");
+        using var host = new HeadlessSessionHost(
+            Descriptor(),
+            credential,
+            new HeadlessDiagnosticWriter(TextWriter.Null),
+            operations);
+        Assert.Equal(
+            RuntimeSessionStartStatus.Connected,
+            host.Start().Status);
+        var interfaceText = new List<string>();
+
+        // A bare "/" is retail's degenerate-prefix case (no letter verb) —
+        // ChatCommandRouter refuses it locally instead of sending it to the
+        // server or speech (ChatCommandRouterTests.
+        // DegeneratePrefix_UnknownCommand_ShowsRefusal_ViaInterfaceTextSeam
+        // pins the exact same text for the graphical route).
+        SubmitOutcome outcome = host.SubmitConsoleLine(
+            "/",
+            interfaceText.Add);
+
+        Assert.Equal(SubmitOutcome.UnknownCommand, outcome);
+        string text = Assert.Single(interfaceText);
+        Assert.Contains("Unknown command:", text);
+    }
+
+    private static bool WaitForEndOfInput(HeadlessConsoleController controller) =>
+        controller.Reader.EndOfInput.Wait(TimeSpan.FromSeconds(5));
+
+    private static uint ActionOpcode(byte[] body) =>
+        BinaryPrimitives.ReadUInt32LittleEndian(body.AsSpan(8, sizeof(uint)));
+
+    private static string TalkText(byte[] body)
+    {
+        ushort length = BinaryPrimitives.ReadUInt16LittleEndian(
+            body.AsSpan(12, sizeof(ushort)));
+        return Encoding.ASCII.GetString(body, 14, length);
+    }
+
+    private static HeadlessSessionDescriptor Descriptor() => new()
+    {
+        Id = "console-bot",
+        Endpoint = new HeadlessEndpointDescriptor
+        {
+            Host = "127.0.0.1",
+            Port = 9000,
+        },
+        Account = "account",
+        Character = new HeadlessCharacterSelector
+        {
+            Name = "headless",
+        },
+        Policy = new HeadlessBotPolicyDescriptor
+        {
+            Id = "idle",
+        },
+        Credential = new HeadlessCredentialReference
+        {
+            Provider = HeadlessCredentialProviderKind.Environment,
+            Reference = "CONSOLE_BOT_PASSWORD",
+        },
+    };
+
+    private sealed class FixtureSessionOperations : ILiveSessionOperations
+    {
+        public Action<byte[]>? GameActionCapture { get; init; }
+
+        public CharacterList.Parsed? Characters { get; init; } = new(
+            0u,
+            [
+                new CharacterList.Character(0x50000001u, "Other", 0u),
+                new CharacterList.Character(0x50000002u, "Headless", 0u),
+            ],
+            [],
+            11,
+            "account",
+            true,
+            true);
+
+        public IPEndPoint ResolveEndpoint(string host, int port) =>
+            new(IPAddress.Loopback, port);
+
+        public WorldSession CreateSession(IPEndPoint endpoint)
+        {
+            var session = new WorldSession(endpoint);
+            session.GameActionCapture = GameActionCapture;
+            return session;
+        }
+
+        public void Connect(WorldSession session, string user, string password)
+        {
+        }
+
+        public CharacterList.Parsed? GetCharacters(WorldSession session) =>
+            Characters;
+
+        public void EnterWorld(WorldSession session, int activeCharacterIndex)
+        {
+        }
+
+        public void Tick(WorldSession session)
+        {
+        }
+
+        public void DisposeSession(WorldSession session) => session.Dispose();
+    }
+}