Unable to sign in to GitHub Copilot using Positron Assistant on a Linux installation

[mark-andrews]

I have a GitHub account with Copilot enabled.
I am on Linux.
I can use GH Copilot in VS Code and in the terminal, so I can authenticate myself to use Copilot on this Linux installation.
On Positron, I can sign in to GitHub and I can use GitHub extensions like GitHub Pull Requests.
Using the AI Assistant, I can use Anthropic via an API key.
However, in the AI Assistant, I can not sign in to use GitHub Copilot.
Here's the error I get

and if I click Sign In again, I get

I don't know what these errors mean. I have tried everything and had long discussions with ChatGPT trying to get to the bottom of it, but now I'm stumped. I am not sure what the problem is or what to try next: GitHub in Positron works; AI Assistant with Anthropic works; Copilot in VS Code works; All on this Linux installation. To that I would add that I can use GitHub Copilot via the AI Assistant on Positron on Windows.

Here's the Positron installation information:

Positron Version: 2025.10.1 build 4
Code - OSS Version: 1.103.0
Commit: b13dd1ca4803bc04a4a9165395b589b8caf4ab58
Date: 2025-10-15T00:40:08.583Z
Electron: 37.2.3
Chromium: 138.0.7204.100
Node.js: 22.17.0
V8: 13.8.500258-electron.0
OS: Linux x64 6.17.3-arch2-1

I'm on Arch Linux, but installed the latest Positron via the x64 deb installer at https://positron.posit.co/download.html

Are there any reported incidents from others of trouble signing in to GitHub Copilot via the AI Assistant on Linux? Has anyone successful done this?

[adamhigerd]

To preface: Arch Linux isn't one of the supported platforms and we don't perform any official testing on it. While I am a Posit employee, I'm answering this as a fellow Arch Linux user, not in any sort of official capacity. (I'm not even on the Positron team.)

That said... It works for me. The only difference in the listed information is that I'm still on kernel 6.17.1 because I haven't updated in a bit.

So I'm guessing the difference is in how you installed it. How did you do it? For me, since there's not a PKGBUILD, I used dpkg -x to unpack Positron-2025.10.1-4-x64.deb into a folder and then moved the contents into place by hand. It started right up. I was able to log into GitHub using OAuth and use Positron Assistant to analyze some sample code.

(Side note: Copilot in VS Code doesn't use copilot-language-server, so that would explain the difference in behavior between that and Positron. Microsoft currently doesn't permit other tools to use the mechanism used in VS Code.)

[mark-andrews]

Hi @adamhigerd Thanks for the comments. It is very reassuring to hear that it works for others, so I just have to figure out what's wrong with my setup.
I install from the PKGBUILD in the AUR: https://aur.archlinux.org/packages/positron-ide-devel-bin
I have been doing it this way for around one year and have not had problems ever, but maybe I should another approach and see what happens. I should also see what happens on a fresh Ubuntu install.

[adamhigerd]

@mark-andrews Now how did I manage to miss that PKGBUILD there when I was looking for it? I must have made a typo or something. Looking at it, I don't see why that shouldn't work. I can only imagine there must be some sort of dependency mismatch.

If you run /usr/share/positron/resources/app/extensions/positron-assistant/resources/copilot/copilot-language-server --stdio at the command line, do you get any error messages? (It should just sit there waiting on input without outputting anything if it's working; just ctrl+C it.)

[mark-andrews]

Hi @adamhigerd Thanks for the advice.

I just installed Ubuntu on a virtual box and installed Positron. Positron Assistant and GitHub Copilot worked perfectly as advertised. So at at least I can get it working properly on Linux. So something is maybe wrong with either the PKGBUILD I am using, though as mentioned, I've been using this for around a year with no trouble, and there's nothing else causing trouble at the moment, so it must be something small with this PKGBUILD or else it is something else.

The copilot-language-server command is not working as expected on Arch.
On Ubuntu, I did
/usr/share/positron/resources/app/extensions/positron-assistant/resources/copilot/copilot-language-server --stdio
and it behaved exactly as you described.
While on Arch, I get

> /usr/share/positron/resources/app/extensions/positron-assistant/resources/copilot/copilot-language-server --stdio
Pkg: Error reading from file.

That's very useful info.

Looking at it further, on Ubuntu, I have

> file /usr/share/positron/resources/app/extensions/positron-assistant/resources/copilot/copilot-language-server  
/usr/share/positron/resources/app/extensions/positron-assistant/resources/copilot/copilot-language-server: ELF 64-bit LSB executable, x86-64, version 1 (GNU/Linux), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, BuildID[sha1]=01df572ab8d52481a8ffd22d2f268c95e22ef2b9, for GNU/Linux 3.2.0, stripped

and this identical, even the same build sha1, on Arch.

However, the sha256sum and file size in bytes of the two files differ, so something got corrupted on Arch I presume. Not sure how or why.

I think I will get to the bottom of this now, one way or the other. And it could be something very specific to my current setup, and not affect other users. But as soon as I figure it out, I will post back here just for the record.

[mark-andrews]

I have now have it working.
With more than a little help from GitHub Copilot, I made a new PKGBUILD. For any other Arch Linux user who might find it useful, it is available here: https://github.com/mark-andrews/positron-ide-archlinux-installer (it goes without saying, I hope, that I can provide no guarantees whatsoever about this installer; but it does work well for me 😄 ).

I still don't know what the problem was with the PKGBUILD on Arch AUR. I tried it in a virtual box with a fresh minimal Arch Linux but encountered the exact same problem as I did on my main desktop, specifically a corrupted copilot-language-server file. I don't know how or why that happened because that file just needed to be copied from the contents of the deb installer.

Thanks again @adamhigerd. I don't think I would ever have tracked down the source of the problem if you had not suggested looking at the copilot-language-server.

[adamhigerd]

Yeah, I have no idea what's up with that either. I can only imagine that it must have been some sort of one-off hiccup, and I should have thought to suggest just uninstalling and reinstalling it.

[wamalab]

I get the same error message and I have the same circumstances as @mark-andrews, except that I am on an enterprise windows machine.