Allow configuring custom skill marketplaces/registries for Copilot CLI (private/internal sources like Azure DevOps, GHE, etc.)

[pomianowski]

Describe the feature or problem you'd like to solve

Add support for custom marketplaces/registries as skill sources, in addition to any default/public source

Proposed solution

Copilot CLI “skills” are most valuable when teams can share and reuse them across an organization. In many companies, skills cannot be published to a public registry/marketplace due to:

• security/compliance constraints,
• proprietary/internal code and workflows,
• air-gapped or restricted networks,
• the need for version pinning and controlled rollout.

As a result, teams end up duplicating skills, copying scripts manually, or forking tooling.

Example prompts or workflows

/plugin marketplace add https://git.lepo.co/_git/copilot

Additional context

There is need for different authentication support

• token-based auth (PAT/Bearer),
• Windows NTLM
• environment-based credential discovery,
• optional interactive login where applicable.