Communication error with Copilot CLI: The JSON-RPC connection with the remote party was lost before the request could complete.

[wullemsb]

I followed the getting started guide as mentioned here.

I created a new console app using .NET 10 and included the Github Copilot SDK(0.1.19).

When running the application, I gett the following error on the CreateSessionAsync line.

An exception of type 'System.IO.IOException' occurred in System.Private.CoreLib.dll but was not handled in user code
Communication error with Copilot CLI: The JSON-RPC connection with the remote party was lost before the request could complete.

Executing the CLI directly works without any problem.

[github-actions]

Thanks for reporting this issue, @wullemsb!

I've labeled this as a bug for the .NET SDK (sdk/dotnet) and added needs-info since we'll need a few more details to help troubleshoot:

1. Operating System: What OS are you running on (Windows, macOS, Linux)?
2. CLI Version: What version of the GitHub CLI do you have installed? (gh --version)
3. Copilot CLI Extension: Can you confirm the Copilot CLI extension is installed? (gh extension list)
4. Code Sample: Could you share the minimal code that reproduces this error (especially how you're initializing the CopilotClient and calling CreateSessionAsync)?
5. Full Stack Trace: If possible, please share the complete exception stack trace.

Since the CLI works when executed directly, this suggests an issue with how the SDK is launching or communicating with the CLI process.

AI generated by Issue Triage Agent

[patniko]

Would be helpful to have a repro. Mind sharing CLI and SDK version #? We'll investigate other ways this might occur in parallel.

[ViralShah6438]

I have the same issue. I followed the getting started guide. I am using VS Code (1.108.2 version), .Net 10 and GitHub.Copilot.SDK (0.1.19).

Let me know if you need further information. Also, please let us know tentative timeline to address this issue.

[AlphaHyperGiant]

Advise - LLC - to B2B As SaaS Use Waterfall scrum Agile Network Channel Partners- Skky Media

…

On Thu, Jan 29, 2026 at 2:08 PM ViralShah6438 ***@***.***> wrote: *ViralShah6438* left a comment (github/copilot-sdk#253) <#253 (comment)> I have the same issue. I followed the getting started guide <https://github.com/github/copilot-sdk/blob/main/docs/getting-started.md>. I am using VS Code (1.108.2 version), .Net 10 and GitHub.Copilot.SDK (0.1.19). Let me know if you need further information. Also, please let us know tentative timeline to address this issue. image.png (view on web) <https://github.com/user-attachments/assets/b5890112-e8a3-4983-bc32-21288a2ac1d7> — Reply to this email directly, view it on GitHub <#253 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/A5BBPJFWSJFKVKEFLJ5M7FT4JJLDVAVCNFSM6AAAAACTJQNNP2VHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZTQMJZG4ZTAMJWGY> . You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>

[AlphaHyperGiant]

Archival

…

On Thu, Jan 29, 2026 at 2:41 PM Jim Ben Hurst ***@***.***> wrote: Advise - LLC - to B2B As SaaS Use Waterfall scrum Agile Network Channel Partners- Skky Media On Thu, Jan 29, 2026 at 2:08 PM ViralShah6438 ***@***.***> wrote: > *ViralShah6438* left a comment (github/copilot-sdk#253) > <#253 (comment)> > > I have the same issue. I followed the getting started guide > <https://github.com/github/copilot-sdk/blob/main/docs/getting-started.md>. > I am using VS Code (1.108.2 version), .Net 10 and GitHub.Copilot.SDK > (0.1.19). > > Let me know if you need further information. Also, please let us know > tentative timeline to address this issue. > image.png (view on web) > <https://github.com/user-attachments/assets/b5890112-e8a3-4983-bc32-21288a2ac1d7> > > — > Reply to this email directly, view it on GitHub > <#253 (comment)>, > or unsubscribe > <https://github.com/notifications/unsubscribe-auth/A5BBPJFWSJFKVKEFLJ5M7FT4JJLDVAVCNFSM6AAAAACTJQNNP2VHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZTQMJZG4ZTAMJWGY> > . > You are receiving this because you are subscribed to this thread.Message > ID: ***@***.***> >

[wullemsb]

Operating System: Windows
Copilot CLI Version: 0.0.348
Github CLI Version: 2.86.0
Copilot CLI Extension: no installed extensions found
Code Sample: Could you share the minimal code that reproduces this error (especially how you're initializing the CopilotClient and calling CreateSessionAsync)?

await using var client = new CopilotClient();
await using var session = await client.CreateSessionAsync(new SessionConfig
{
    Model = "claude-sonnet-4.5",
    Streaming = false,
});

Full Stack Trace:

System.IO.IOException
  HResult=0x80131620
  Message=Communication error with Copilot CLI: The JSON-RPC connection with the remote party was lost before the request could complete.
  Source=GitHub.Copilot.SDK
  StackTrace:
   at GitHub.Copilot.SDK.CopilotClient.<InvokeRpcAsync>d__25`1.MoveNext()
   at GitHub.Copilot.SDK.CopilotClient.<VerifyProtocolVersionAsync>d__27.MoveNext()
   at GitHub.Copilot.SDK.CopilotClient.<<StartAsync>g__StartCoreAsync|9_0>d.MoveNext()
   at GitHub.Copilot.SDK.CopilotClient.<CleanupConnectionAsync>d__13.MoveNext()
   at GitHub.Copilot.SDK.CopilotClient.<ForceStopAsync>d__11.MoveNext()
   at GitHub.Copilot.SDK.CopilotClient.<DisposeAsync>d__38.MoveNext()
   at Program.<<Main>$>d__0.MoveNext() in D:\Projects\Test\CopilotSDKTryOut\CopilotSDKTryOut\Program.cs:line 31

  This exception was originally thrown at this call stack:
    [External Code]

Inner Exception 1:
ConnectionLostException: The JSON-RPC connection with the remote party was lost before the request could complete.

[showpune]

We have the same problem in github pipeline and we always install latest copilot CLI and SDK. This issue happend randomly,

[Yuno-Liu]

The same problem also occurs when using the gemini ACP

Copilot CLI Version：0.0.400
gemini CLI Version：0.26.0
.net version：.net 10
GitHub.Copilot.SDK：0.1.20

static async Task Main()
{
    var copilotClientOptions = new CopilotClientOptions(){
        CliPath = "gemini",
        CliArgs = ["--experimental-acp"],
    };
    await using var client = new CopilotClient(copilotClientOptions);
    await using var session = await client.CreateSessionAsync(new SessionConfig
    {
        Model = "gemini-3-pro-preview",
        Streaming = false,
    });
    session.On(ev =>
    {
        if (ev is AssistantMessageDeltaEvent deltaEvent)
        {
            Console.Write(deltaEvent.Data.DeltaContent);
        }
        if (ev is SessionIdleEvent)
        {
            Console.WriteLine();
        }
    });
    await session.SendAndWaitAsync(new MessageOptions
    {
        Prompt = "1+1=?",
    });
}