Expand BYOK with why and FAQ (#8299)

* Expand BYOK with why and FAQ

* Add considerations for BYOK

* Incorporate feedback

Author: ntrogh

docs/copilot/language-models.md

@@ -10,7 +10,9 @@ Copilot in Visual Studio Code offers different built-in language models that are
 
 ## Choose the right model for your task
 
-Some models are optimized for fast coding tasks, while others are better suited for slower planning and reasoning tasks.
+By default, Copilot Chat uses a base model to provide fast, capable responses for a wide range of tasks, such as coding, summarization, knowledge-based questions, reasoning, and more.
+
+However, you are not limited to using this model. You can choose from a selection of other models, each with its own particular strengths. You may have a favorite model that you like to use, or you might prefer to use a particular model for inquiring about a specific subject.
 
 | Model type | Models |
 |-----------|--------|
@@ -26,6 +28,20 @@ The list of [models available in Copilot](https://docs.github.com/en/copilot/usi
 > [!NOTE]
 > If you are a Copilot Business or Enterprise user, your administrator needs to enable certain models for your organization by opting in to `Editor Preview Features` in the [Copilot policy settings](https://docs.github.com/en/enterprise-cloud@latest/copilot/managing-copilot/managing-github-copilot-in-your-organization/managing-policies-for-copilot-in-your-organization#enabling-copilot-features-in-your-organization) on GitHub.com.
 
+## Why use your own language model API key?
+
+Developers can now leverage models directly from Anthropic, Azure, Google, OpenAI, OpenRouter, or Ollama directly by providing a valid API key. Learn how to [use your own API in VS Code](#bring-your-own-language-model-key).
+
+Using your own language model API key in VS Code has several advantages:
+
+- **Model choice**: access hundreds of models from different providers, beyond the built-in models.
+- **Experimentation**: experiment with new models or features that are not yet available in the built-in models.
+- **Local compute**: use your own compute for one of the models already supported in GitHub Copilot or to run models not yet available.
+- **Greater control**: by using your own key, you can bypass the standard rate limits and restrictions imposed on the built-in models.
+
+> [!IMPORTANT]
+> This feature is currently in preview and is only available for GitHub Copilot Free and GitHub Copilot Pro users.
+
 ## Change the model for chat conversations
 
 Use the language model picker in the chat input field to change the model that is used for chat conversations and code editing.
@@ -85,6 +101,23 @@ To update the provider details, such as the API key or endpoint URL:
 
 1. Update the provider details, such as the API key or endpoint URL.
 
+### Considerations
+
+There are a number of considerations when using your own language model API key in VS Code:
+
+- Bringing your own model only applies to the chat experience and doesn't impact code completions or other AI-powered features in VS Code, such as commit-message generation.
+- The capabilities of each model might differ from the built-in models and could affect the chat experience. For example, some models might not support vision or tool calling.
+- The Copilot API is still used for some tasks, such as sending embeddings, repository indexing, query refinement, intent detection, and side queries.
+- When using your own model, there is no guarantee that responsible AI filtering is applied to the model's output.
+
+## Frequently asked questions
+
+### Why is bring your own model key only available for Copilot Free and Copilot Pro?
+
+Bringing your own model key is only available for Copilot Free and Copilot Pro because it's mainly meant to allow users experiment with the newest models the moment they are announced, and not yet available as a built-in model in Copilot. Copilot Business and Enterprise users can still use the built-in, managed models.
+
+Bringing your own model key will come to Copilot Business and Enterprise plans later this year, as we better understand the requirements that organizations have for using this functionality at scale.
+
 ## Related resources
 
-* [Available language models in GitHub Copilot](https://docs.github.com/en/copilot/using-github-copilot/ai-models/changing-the-ai-model-for-copilot-chat?tool=vscode)
+- [Available language models in GitHub Copilot](https://docs.github.com/en/copilot/using-github-copilot/ai-models/changing-the-ai-model-for-copilot-chat?tool=vscode)