Claude Model Provider Extension for VS Code

This Visual Studio Code extension contributes language models that can be used in the chat view and also by other extensions that allow selecting language models.

Why?

Adding your Anthropic API key directly in Visual Studio Code only allows using Claude models from the Chat sidebar. Trying to use the models from another extension will produce system: text content blocks must be non-empty errors.

This extension allows using Claude models from other extensions like LGTM as well.

Models

Models are fetched from the Anthropic API, so newer models such as Claude Opus 4.8 and Sonnet 5 are available automatically, without an extension update.

Use in Chat

Extension-provided language models may not be visible in the chat model picker. Use the Chat: Manage Language Models command to list all models, and toggle visibility for the model(s) you want.

Note: If you only want to use Claude in the Chat view, you don't need this extension. Visual Studio Code's built-in "bring your own key" (BYOK) support should work. (Open the Chat: Manage Language Models command and click Add Models > Anthropic)

Use from another extension

Any extension can send requests to these models through VS Code's Language Model API (vscode.lm), without depending on this extension directly.

Select a model with a chat model selector, then stream a response:

import * as vscode from 'vscode';

const [model] = await vscode.lm.selectChatModels({
    vendor: 'claude-model-provider', // omit to allow any provider
    // family: 'claude',
    // id: 'claude-sonnet-4-5-20250929',
});
if (!model) {
    return; // extension not installed, or no models available
}

const messages = [
    vscode.LanguageModelChatMessage.User('Explain this code: ...'),
];
const response = await model.sendRequest(messages, {}, cancelToken);
for await (const chunk of response.text) {
    // chunk is of type `string`
}

Notes:

• The user is asked for consent the first time your extension sends a request. Pass justification in the request options to explain why you need access.
• Tool calling is supported: pass tools in the request options, and handle LanguageModelToolCallPart items from response.stream (rather than response.text, which yields text only). See Tool calling.

Setup

The extension will prompt you to enter your API key when you first use it. It's recommended to generate a new key from the Claude Console.

To change your key later, run the Claude Model Provider: Update API Key command from the Command Palette.

Settings

• Claude-model-provider: Prompt Caching (default: enabled): caches the request prefix (tool definitions and prior messages) via Anthropic's prompt caching, so later turns in a conversation re-read the cached prefix at reduced cost. If you mainly send single requests rather than multi-turn conversations, this can moderately increase costs and you may want to turn this off.

Disclaimer

This extension is not associated with Anthropic. It's an independent project that uses Anthropic's API.

Usage is billed to your own account at standard API rates.

Support

If you encounter any issues or have questions, please open an issue on the GitHub repository.