github/copilot-sdk · error · ArgumentException

CopilotClientOptions.Telemetry is not supported with…

Error message

CopilotClientOptions.Telemetry is not supported with RuntimeConnection.ForInProcess(): telemetry configuration is lowered to environment variables read by native runtime code running in the shared host process, so per-client telemetry cannot be honored in-process. Configure telemetry via the host process environment, or use a child-process transport.

What it means

CopilotClient throws this ArgumentException when CopilotClientOptions.Telemetry is set with RuntimeConnection.ForInProcess(). Telemetry configuration is lowered to environment variables read by the native runtime; in-process that native code runs in the shared host process, so per-client telemetry cannot be honored. The constructor rejects the combination instead of silently misapplying settings.

Solutions

Set options.Telemetry to null when using ForInProcess().
Configure telemetry via host process environment variables instead.
Use RuntimeConnection.ForStdio() (child-process transport) if per-client telemetry configuration is required.

Example fix

// before
var options = new CopilotClientOptions { Telemetry = new TelemetryOptions { Enabled = true } };
var client = new CopilotClient(options, RuntimeConnection.ForInProcess());
// after
var options = new CopilotClientOptions { Telemetry = null };
// configure telemetry via host env vars instead
var client = new CopilotClient(options, RuntimeConnection.ForInProcess());

Defensive patterns

Strategy: validation

Validate before calling

if (connection is InProcessRuntimeConnection && options.Telemetry is not null)
    throw new InvalidOperationException("Configure telemetry via host process env for in-process transport.");

Type guard

static bool AllowsOptionsTelemetry(RuntimeConnection c) => c is not InProcessRuntimeConnection;

Try / catch

try { client = new CopilotClient(options, connection); }
catch (ArgumentException ex) when (ex.Message.Contains("Telemetry")) { options.Telemetry = null; client = new CopilotClient(options, connection); }

Prevention

Null out telemetry settings when switching to in-process
Centralize telemetry config in host environment
Document transport restrictions next to options construction

When it happens

Trigger: new CopilotClient(options, RuntimeConnection.ForInProcess()) where options.Telemetry is non-null. Checked by ValidateEnvironmentOptions during CopilotClient construction.

Common situations: Reusing the same options object for stdio and in-process connections; copying configuration that included telemetry settings when migrating to in-process transport.

Understand the failure class

Background: Conflicting config options: "cannot be used together" — configuration validation errors across open-source libraries — this error's family across 162 libraries.

Related errors

AI-assisted analysis of github/copilot-sdk@cd8cf15dc3 (2026-09-09). Data as JSON: /api/errors/70e4be71a0fe9cf2. Report an issue: GitHub.

Appendix: source

Thrown at dotnet/src/Client.cs:242

    /// telemetry options that lower to environment variables are rejected there.
    /// </summary>
    private static void ValidateEnvironmentOptions(CopilotClientOptions options, RuntimeConnection connection)
    {
        if (connection is InProcessRuntimeConnection)
        {
            if (options.Environment is not null)
            {
                throw new ArgumentException(
                    $"{nameof(CopilotClientOptions)}.{nameof(CopilotClientOptions.Environment)} is not supported with " +
                    $"{nameof(RuntimeConnection)}.{nameof(RuntimeConnection.ForInProcess)}(): the in-process transport " +
                    "loads the native runtime into the shared host process, whose single environment block cannot carry " +
                    "per-client values. Set the variables on the host process environment instead.",
                    nameof(options));
            }

            if (options.Telemetry is not null)
            {
                throw new ArgumentException(
                    $"{nameof(CopilotClientOptions)}.{nameof(CopilotClientOptions.Telemetry)} is not supported with " +
                    $"{nameof(RuntimeConnection)}.{nameof(RuntimeConnection.ForInProcess)}(): telemetry configuration is " +
                    "lowered to environment variables read by native runtime code running in the shared host process, so " +
                    "per-client telemetry cannot be honored in-process. Configure telemetry via the host process " +
                    "environment, or use a child-process transport.",
                    nameof(options));
            }

            if (options.WorkingDirectory is not null)
            {
                throw new ArgumentException(
                    $"{nameof(CopilotClientOptions)}.{nameof(CopilotClientOptions.WorkingDirectory)} is not supported with " +
                    $"{nameof(RuntimeConnection)}.{nameof(RuntimeConnection.ForInProcess)}(): the in-process transport hosts " +
                    "the native runtime in the shared host process and spawns the worker without a working-directory " +
                    "parameter, so a per-client working directory cannot be honored in-process. Use a child-process " +
                    "transport, or set the process working directory before creating the client.",
                    nameof(options));
            }

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