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Using VS Code Language Model API With Roo Code

Roo Code includes experimental support for the VS Code Language Model API. This API allows extensions to provide access to language models directly within VS Code. This means you can potentially use models from:

  • GitHub Copilot: If you have a Copilot subscription and the extension installed.
  • Other VS Code Extensions: Any extension that implements the Language Model API.

Important: This integration is highly experimental and may not work as expected. It is dependent on other extensions correctly implementing the VS Code Language Model API.

Prerequisites​

  • VS Code: The Language Model API is available through VS Code (and is not currently supported by Cursor).
  • A Language Model Provider Extension: You need an extension that provides a language model. Examples include:
    • GitHub Copilot: If you have a Copilot subscription, the GitHub Copilot and GitHub Copilot Chat extensions can provide models.
    • Other Extensions: Search the VS Code Marketplace for extensions that mention "Language Model API" or "lm". There may be other experimental extensions available.

Configuration​

  1. Open Roo Code Settings: Click the gear icon () in the Roo Code panel.
  2. Select Provider: Choose "VS Code LM API" from the "API Provider" dropdown.
  3. Select Model: The "Language Model" dropdown will (eventually) list available models. The format is vendor/family. For example, if you have Copilot, you might see options like:
    • copilot - claude-3.5-sonnet
    • copilot - o3-mini
    • copilot - o1-ga
    • copilot - gemini-2.0-flash

Limitations​

  • Experimental API: The VS Code Language Model API is still under development. Expect changes and potential instability.
  • Extension Dependent: This feature relies entirely on other extensions providing models. Roo Code cannot directly control which models are available.
  • Limited Functionality: The VS Code Language Model API may not support all the features of other API providers (e.g., image input, streaming, detailed usage information).
  • No Direct Cost Control: You are subject to the pricing and terms of the extension providing the model. Roo Code cannot directly track or limit costs.

Troubleshooting​

  • No Models Appear:
    • Ensure you have VS Code installed.
    • Ensure you have a language model provider extension installed and enabled (e.g., GitHub Copilot, GitHub Copilot Chat).
    • If using Copilot, make sure that you have sent a Copilot Chat message using the model you would like to use.
  • Unexpected Behavior: If you encounter unexpected behavior, it's likely an issue with the underlying Language Model API or the provider extension. Consider reporting the issue to the provider extension's developers.

Feedback​

Because this feature is experimental, your feedback is extremely valuable! Please report any issues or suggestions on the Roo Code GitHub Issues page.