git-ecosystem/git-credential-manager · error · InvalidOperationException

No available interaction modes.

Error message

No available interaction modes.

What it means

Thrown from GetTokenForUserInteractiveAsync when InteractionMode.Auto is requested (or defaulted) but none of the interactive mechanisms — embedded webview, system webview, or device code flow — are available on the current platform/configuration. The library cannot perform user interactive authentication at all, so it fails fast with this InvalidOperationException.

Solutions

1. Verify which modes are available with IsEmbeddedWebViewAvailable/IsSystemWebViewAvailable/IsDeviceCodeAvailable before requesting Auto mode.
2. Explicitly pass InteractionMode.DeviceCode and ensure device code flow is supported (network access to the device authorization endpoint).
3. Run in an environment with a browser or desktop session (GUI available) so a webview mode can be used.
4. Pre-authenticate on a machine with a browser and copy credentials/tokens to the headless environment.

Example fix

// before
var token = await auth.GetTokenForUserAsync(scopes); // Auto -> throws on headless box
// after
var token = await auth.GetTokenForUserAsync(scopes, Interaction: InteractionMode.DeviceCode);

bool anyMode = IsEmbeddedWebViewAvailable() || IsSystemWebViewAvailable() || IsDeviceCodeAvailable();
if (!anyMode) throw new InvalidOperationException("No interactive authentication available in this environment.");

try
{
    token = await auth.GetTokenForUserAsync(scopes);
}
catch (InvalidOperationException ex) when (ex.Message == "No available interaction modes.")
{
    // fall back to device code flow or fail with a clear message
    token = await auth.GetTokenForUserAsync(scopes, Interaction: InteractionMode.DeviceCode);
}

When it happens

Trigger: Calling GetTokenForUserAsync (which resolves to GetTokenForUserInteractiveAsync) with InteractionMode.Auto on a headless environment (SSH session, CI runner, container) where no webview is available and the device code endpoint/flow is unavailable or disabled.

Common situations: Running GCM or a tool using this library on a headless Linux server, inside Docker, over SSH without a browser, or on a stripped-down platform where MSAL reports no supported broker/webview and device code flow is unavailable.

Understand the failure class

Background: "unsupported platform" / "not supported on this platform" errors: what they mean and how to fix them — this error's family across 47 libraries.

Related errors

• Browser authentication requires a desktop session
• Must specify at least one AuthenticationModes
• Unknown authentication mode
• At least one AuthenticationModes must be supplied
• Missing username in response

AI-assisted analysis of git-ecosystem/git-credential-manager@e8ce762cd0 (2026-09-11). Data as JSON: /api/errors/878ffb7bc0a6fa26. Report an issue: GitHub.

Appendix: source

Thrown at src/Core/Authentication/Entra/EntraAuthentication.PublicClient.cs:300

            Context.Trace.WriteLine($"Interaction mode overriden to '{mode}'.");
            interactionMode = mode;
        }

        switch (interactionMode)
        {
            // Try to use the most appropriate interaction mode available
            case InteractionMode.Auto:
                Context.Trace.WriteLine("Resolving interactive mode auto...");
                if (IsEmbeddedWebViewAvailable())
                    goto case InteractionMode.EmbeddedWebView;

                if (IsSystemWebViewAvailable())
                    goto case InteractionMode.SystemWebView;

                if (IsDeviceCodeAvailable())
                    goto case InteractionMode.DeviceCode;

                throw new InvalidOperationException("No available interaction modes.");

            case InteractionMode.EmbeddedWebView:
                Context.Trace.WriteLine("Performing interactive authentication via embedded webview...");
                return await app.AcquireTokenInteractive(scopes)
                    .WithUseEmbeddedWebView(true)
                    .WithEmbeddedWebViewOptions(GetEmbeddedWebViewOptions())
                    .ExecuteAsync(ct);

            case InteractionMode.SystemWebView:
                Context.Trace.WriteLine("Performing interactive authentication via system webview...");
                Context.Console.WriteInfo("opening browser to complete authentication...");
                return await app.AcquireTokenInteractive(scopes)
                    .WithUseEmbeddedWebView(false)
                    .WithSystemWebViewOptions(GetSystemWebViewOptions())
                    .ExecuteAsync(ct);

            case InteractionMode.DeviceCode:
                Context.Trace.WriteLine("Performing interactive authentication via device code...");

View on GitHub (pinned to e8ce762cd0)