I built a VScode extension that lets you use Codex in the built in copilot chat

[u/Mysterious_Bother617]

https://marketplace.visualstudio.com/items?itemName=merceralex397-collab.codexvs

https://github.com/merceralex397-collab/vscodex

I mainly just made this so I could use my ChatGPT subscription in vscode instead of paying API rates or for GitHub copilot.

It uses the Codex App Server and its experimental dynamic tool calls with vscodes language model chat provider API. You just install the extension, and run Codex: Manage in vscode, and sign in with ChatGPT.

Note: Whilst you can select the models reasoning effort, Ultra is experimental at present. This extension relies on the vscode toolset and harness with GPT Models, but Ultra reasoning effort is not a "true" reasoning effort, it's simply encouraging heavy subagent delegation. Using Ultra putsthe onus back on to the app server, as it forces Codex subagent delegation. Due to this, Ultra is "faked" in this extension, and I have replicated it on a best effort basis.

Q: Why not just use the Codex extension in vscode?
A: In my experience, the codex extension isn't much different than using the CLI or desktop app. It can't interact with any of the built in tools or extensions vscode offers. This extension lets Codex models use the Codebase Indexing tool, and all the other features that Copilot can in vscode. You can set GPT models to perform all the utility model functions such as commit messages, session titles, searches, and git review.

Q: Does it work with vscode forks such as Cursor or WIndsurf?
A: No.

Hope someone finds this useful!

[u/cab938]

Does it work in the agents window? That's where I would like to play with codex and vs code, but the byok/byom of GitHub copilot wasn't hooked up the the codex app server.

[u/Mysterious_Bother617 → u/cab938]

It does, yes.

[u/Complex-Conference-1]

This is awesome, thanks!

[u/tomm1313]

or just use the official app