Alternate environment variable for PAT

[jonathanmorley]

Describe the feature or problem you'd like to solve

When I provide a fine grained PAT using GH_TOKEN or GITHUB_TOKEN, and the LLM wants to run gh, it uses the token I provided for copilot.

Proposed solution

Introduce a new environment variable (e.g. COPILOT_GH_TOKEN) that can be provided, and would be used by copilot CLI, but not by the gh CLI.

Example prompts or workflows

No response

Additional context

No response

[EvanBoyle]

The gh CLI is currently invoked via the shell tool and for security reasons we explicitly filter out GITHUB_TOKEN from requests to the that tool.

I have run into this myself and would love to see a workaround provided via an alternative env var that users can opt into cc @cmart12 @RyanHecht otherwise, the GH CLI is effectively useless within the copilot CLI