Agent hangs when executed in GitHub Action

[JasonYeMSFT]

Steps to reproduce:

1. Create a GitHub repo with a package.json using @github/copilot-sdk as a dependency. Add a bugRepro.mjs file to the repo with the following content

import { CopilotClient } from "@github/copilot-sdk";

async function main() {
    const client = new CopilotClient({
        logLevel: 'all',
    });

    const session = await client.createSession({
        model: 'claude-sonnet-4.5',
    });

    const done = new Promise((resolve) => {
        session.on((event) => {
            console.log(`=== session event ${event.type}`);
            if (event.type === 'session.idle') {
                console.log("resolve");
                resolve();
                return;
            }
        });
    });

    await session.send({ prompt: "hello, what can you do?" });
    await done;
    process.exit();
}

main();

2. Install the dependencies and run node bugRepro.mjs. The agent will do some work and finally emit a session.idle event.
3. Create a manual GitHub Action workflow that installs the npm modules, uses mvkaran/setup-copilot-cli@v1 to setup Copilot CLI, and executes the node bugRepro.mjs script.
4. Observe that the agent consistently emits two pending_messages.modified events and then hangs.

[github-actions]

Thank you for reporting this issue, @JasonYeMSFT!

I've labeled this as a bug affecting the sdk/nodejs implementation. The issue appears to be specific to GitHub Actions environments where the agent hangs after emitting pending_messages.modified events instead of completing with a session.idle event.

The reproduction steps are clear and helpful. Our team will investigate why the behavior differs between local execution and GitHub Actions.

AI generated by Issue Triage Agent

[JasonYeMSFT]

After consulting someone who managed to make Copilot SDK work in a workflow, I realized that it has something to do with the fact I was using a classic PAT. I still believe the agent behavior can be improved by making it more obvious that there is permission issue instead of just hanging indefinitely.

[patniko]

Hi @JasonYeMSFT. Will keep it open until I can review with the team, but the classic PAT will be the issue. We are working on a few things over here that should make this much better in the near future. Working to complete the final solution right now.

[thepassle]

I believe I'm running into the same or a similar issue, except in azure pipelines. I'm also using CopilotClient but with a githubToken;

const client = new CopilotClient({
  githubToken: process.env.GHCP_TOKEN,
  useStdio: false,
});

And while my prompt works, it does seem to cause the process to hang (until the azure pipeline times out)