diff --git a/src/ClaudeDo.Worker/Usage/TokenTracker/Interfaces/ITokenTrackerClient.cs b/src/ClaudeDo.Worker/Usage/TokenTracker/Interfaces/ITokenTrackerClient.cs
new file mode 100644
index 00000000..8840b9da
--- /dev/null
+++ b/src/ClaudeDo.Worker/Usage/TokenTracker/Interfaces/ITokenTrackerClient.cs
@@ -0,0 +1,14 @@
+namespace ClaudeDo.Worker.Usage.TokenTracker.Interfaces;
+
+public interface ITokenTrackerClient
+{
+    /// <summary>Checks whether the CLI and a usable Node runtime are present. Never throws.</summary>
+    Task<TokenTrackerProbe> ProbeAsync(CancellationToken ct = default);
+
+    /// <summary>Runs the sessions export. Never throws — a failure comes back as
+    /// <see cref="TokenTrackerRunResult.Ok"/> false plus an error message.</summary>
+    Task<TokenTrackerRunResult> ExportAsync(DateOnly from, DateOnly to, CancellationToken ct = default);
+
+    /// <summary>Runs <c>npm i -g tokentracker-cli</c>, reporting each output line.</summary>
+    Task<TokenTrackerRunResult> InstallAsync(IProgress<string>? output = null, CancellationToken ct = default);
+}
diff --git a/src/ClaudeDo.Worker/Usage/TokenTracker/TokenTrackerClient.cs b/src/ClaudeDo.Worker/Usage/TokenTracker/TokenTrackerClient.cs
new file mode 100644
index 00000000..8f02becd
--- /dev/null
+++ b/src/ClaudeDo.Worker/Usage/TokenTracker/TokenTrackerClient.cs
@@ -0,0 +1,129 @@
+using System.Diagnostics;
+using System.Globalization;
+using ClaudeDo.Data.Environment;
+using ClaudeDo.Worker.Usage.TokenTracker.Interfaces;
+
+namespace ClaudeDo.Worker.Usage.TokenTracker;
+
+/// <summary>
+/// Starts the TokenTracker CLI. Resolution goes through <see cref="ExecutableResolver"/> because
+/// an npm-installed CLI is a <c>.cmd</c> shim, which <c>UseShellExecute = false</c> cannot exec
+/// directly. We deliberately never fall back to <c>npx</c> — that would silently download a
+/// package behind the user's back.
+/// </summary>
+public sealed class TokenTrackerClient : ITokenTrackerClient
+{
+    private static readonly TimeSpan ExportTimeout = TimeSpan.FromSeconds(120);
+    private static readonly TimeSpan ProbeTimeout = TimeSpan.FromSeconds(20);
+    private static readonly TimeSpan InstallTimeout = TimeSpan.FromMinutes(5);
+    private const int MinimumNodeMajor = 20;
+
+    public async Task<TokenTrackerProbe> ProbeAsync(CancellationToken ct = default)
+    {
+        var node = await RunAsync("node", ["--version"], ProbeTimeout, null, ct);
+        var nodeVersion = node.Ok ? node.StdOut.Trim() : null;
+        var nodeOk = NodeMajor(nodeVersion) >= MinimumNodeMajor;
+
+        var cli = await RunAsync(TokenTrackerArgs.Command, TokenTrackerArgs.Version(), ProbeTimeout, null, ct);
+        return cli.Ok
+            ? new TokenTrackerProbe(true, cli.StdOut.Trim(), nodeOk, nodeVersion, null)
+            : new TokenTrackerProbe(false, null, nodeOk, nodeVersion, cli.Error);
+    }
+
+    public Task<TokenTrackerRunResult> ExportAsync(DateOnly from, DateOnly to, CancellationToken ct = default) =>
+        RunAsync(TokenTrackerArgs.Command, TokenTrackerArgs.Export(from, to), ExportTimeout, null, ct);
+
+    public Task<TokenTrackerRunResult> InstallAsync(IProgress<string>? output = null, CancellationToken ct = default) =>
+        RunAsync(TokenTrackerArgs.NpmCommand, TokenTrackerArgs.Install(), InstallTimeout, output, ct);
+
+    /// <summary>Visible for the probe's version parsing; returns 0 when unreadable.</summary>
+    internal static int NodeMajor(string? version)
+    {
+        if (string.IsNullOrWhiteSpace(version)) return 0;
+
+        var trimmed = version.Trim().TrimStart('v', 'V');
+        var major = trimmed.Split('.', 2)[0];
+        return int.TryParse(major, NumberStyles.Integer, CultureInfo.InvariantCulture, out var v) ? v : 0;
+    }
+
+    private static async Task<TokenTrackerRunResult> RunAsync(
+        string command,
+        IReadOnlyList<string> arguments,
+        TimeSpan timeout,
+        IProgress<string>? output,
+        CancellationToken ct)
+    {
+        var resolved = ExecutableResolver.Resolve(command);
+        if (resolved is null)
+            return new TokenTrackerRunResult(false, "", $"'{command}' not found on PATH.");
+
+        var startInfo = new ProcessStartInfo
+        {
+            RedirectStandardOutput = true,
+            RedirectStandardError = true,
+            UseShellExecute = false,
+            CreateNoWindow = true,
+        };
+
+        if (resolved.IsShim)
+        {
+            var shim = ExecutableResolver.BuildShimStartInfo(resolved.Path, arguments);
+            startInfo.FileName = shim.FileName;
+            startInfo.Arguments = shim.Arguments;
+        }
+        else
+        {
+            startInfo.FileName = resolved.Path;
+            foreach (var arg in arguments) startInfo.ArgumentList.Add(arg);
+        }
+
+        using var timeoutCts = CancellationTokenSource.CreateLinkedTokenSource(ct);
+        timeoutCts.CancelAfter(timeout);
+
+        try
+        {
+            using var process = Process.Start(startInfo);
+            if (process is null)
+                return new TokenTrackerRunResult(false, "", $"Could not start '{command}'.");
+
+            // Both pipes are drained concurrently — reading one to the end first deadlocks as
+            // soon as the other fills its buffer, and a full-history export is ~1 MB of stdout.
+            var stdoutTask = process.StandardOutput.ReadToEndAsync(timeoutCts.Token);
+            var stderrTask = ReadLinesAsync(process, output, timeoutCts.Token);
+
+            await process.WaitForExitAsync(timeoutCts.Token);
+            var stdout = await stdoutTask;
+            var stderr = await stderrTask;
+
+            return process.ExitCode == 0
+                ? new TokenTrackerRunResult(true, stdout, null)
+                : new TokenTrackerRunResult(false, stdout,
+                    $"'{command}' exited with code {process.ExitCode}. {Head(stderr)}".TrimEnd());
+        }
+        catch (OperationCanceledException) when (!ct.IsCancellationRequested)
+        {
+            return new TokenTrackerRunResult(false, "", $"'{command}' timed out after {timeout.TotalSeconds:0}s.");
+        }
+        catch (Exception ex)
+        {
+            return new TokenTrackerRunResult(false, "", $"'{command}' failed: {ex.Message}");
+        }
+    }
+
+    private static async Task<string> ReadLinesAsync(Process process, IProgress<string>? output, CancellationToken ct)
+    {
+        var lines = new List<string>();
+        while (await process.StandardError.ReadLineAsync(ct) is { } line)
+        {
+            lines.Add(line);
+            output?.Report(line);
+        }
+        return string.Join(System.Environment.NewLine, lines);
+    }
+
+    private static string Head(string text)
+    {
+        var trimmed = text.Trim();
+        return trimmed.Length <= 300 ? trimmed : trimmed[..300] + "…";
+    }
+}