Support for BYOK to add models into COPILOT CLI Through API Keys

[aosama]

Describe the feature or problem you'd like to solve

As a user of COPILOT CLI, I sometimes need to add new models through BYOK (Bring Your Own Key). This allows me to benefite from using models such as Grok 4.1 and their 1 million token window.

This solves use cases where larger context window models are needed, for example reading a large codebase and planning a major refactor. Another example is using dpecialized models which have better aptitude for dealing with complex mathematics.

Proposed solution

Allow the addition of model providers and API keys into the JSON configuration files of copilot CLI. For exampl,

{
"modelProviders": {
"xai": {
"name": "xAI",
"provider": "openai-compatible",
"baseUrl": "https://api.x.ai/v1",
"apiKey": "${XAI_API_KEY}",
"models": [
{
"id": "grok-3",
"displayName": "Grok 4 (My Key)",
"contextLength": 1000000,
"capabilities": ["tool_use", "vision"]
}
]
}
}
}

Example prompts or workflows

No response

Additional context

 While the model lineup from the co pilot subscription is absolutely fantastic, There are use cases where models from different providers and different from the lineup are needed. Particularly the most pressing need (in my use cases) is the larger context window and the larger GROK models from XAI.

No response

[aosama]

I hope BYOK (bring your own key) will be supported in copilot CLI so users can benefit from running other models not in the built in lineup of the subscription. Primarily models that have 1M token window or 2M token window -- among other use cases