GitHub Copilot

The login-with-copilot command connects the Cosine CLI to your GitHub Copilot subscription. After you sign in, Copilot-backed models appear in the model picker and future requests can be billed through your Copilot account instead of your Cosine account.

Requirement

You need a GitHub Copilot Business or Enterprise license for this login method.

If your account does not have the required Copilot entitlement, the login may complete but Copilot-backed models will not become available in the CLI.

What this enables

After you log in with GitHub Copilot, you can:

select GitHub Copilot models from the model picker
run one-shot prompts with a Copilot-backed model
use Copilot-backed models inside the interactive CLI

This is separate from:

cos login for your Cosine account
cos login-with-chatgpt for ChatGPT-backed models

Run:

cos login-with-copilot

The CLI starts GitHub’s device authorization flow and shows:

a verification URL
a short user code
a browser window, if one can be opened automatically

Device flow

When the login starts:

open the GitHub verification page shown in the terminal
sign in to GitHub, if needed
enter the device code
approve access for the app
return to the terminal and wait for confirmation

You can also prevent the browser from opening automatically:

cos login-with-copilot --no-browser

This is useful on remote machines, inside SSH sessions, or when you want to copy the URL into another browser manually.

When the flow succeeds, the CLI:

stores your Copilot authentication locally
marks Copilot auth as enabled in your CLI config
makes Copilot-backed models available in the model picker

Once logged in, you can start the CLI normally and choose a Copilot model from the model selector, or pass one directly:

cos start --model copilot-claude-sonnet-4.6

Using Copilot models

After login, Copilot-backed models appear under the GitHub Copilot provider in the model picker.

Common workflow:

run cos start
open the model picker
choose a model under GitHub Copilot
continue working normally

You can also use them in non-interactive mode:

cos start --model copilot-claude-sonnet-4.6 --prompt "Explain the authentication flow in this repository"

Troubleshooting

”no Copilot tokens found”

If you see an error like:

no Copilot tokens found; run 'cos login-with-copilot'

run the login command again:

cos login-with-copilot

The browser does not open

Use:

cos login-with-copilot --no-browser

Then open the printed URL manually and enter the displayed code.

A model appears in another tool but not in Cosine

Model availability depends on the GitHub account, Copilot entitlement, and the authentication path GitHub accepts for that session. If a model is rejected:

run cos login-with-copilot again
retry the model
confirm the GitHub account you approved has Copilot access for that model