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This guide configures the chat built into VS Code. Agent extensions keep their own provider settings: if you use Kilo Code in VS Code, follow the Kilo Code guide instead.

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Before you begin

Install VS Code 1.122 or later, create a key on the API Keys page, and choose a model on the Models page.
1

Add a Custom Endpoint

In the Chat view, open the model picker (Models) and select +, or run Chat: Manage Language Models from the Command Palette. The Language Models editor opens.Select Add Models → Custom Endpoint. VS Code asks for these values in turn:
2

Configure the model

VS Code opens chatLanguageModels.json with a LithosAI entry and an empty model. Leave name, vendor, apiKey, and apiType as VS Code wrote them: apiKey refers to the key you entered, which VS Code keeps in secret storage. Replace the empty model under models with the entry below and save the file.The entry below uses moonshotai/Kimi-K3-fast as an example.
Set url to the full Chat Completions endpoint, not the base URL. VS Code treats maxInputTokens plus maxOutputTokens as the context window, so set maxInputTokens to the model’s context window minus maxOutputTokens.To add another model or tier, copy the entry under models and update its id, name, and token limits using the model catalog.
3

Start a conversation

In the Chat view, select New Chat (+), set Session Target to Local, and choose your LithosAI model in the model picker. Select Agent in the agent picker to let the model edit files and run tools.

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Model and reasoning effort

  • Model and tier: Use the model picker in the Chat view.
  • Reasoning effort: In the model picker, select > next to your LithosAI model to open Thinking Effort, then select low, high, or max. VS Code remembers the level for each session.

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Use VS Code without a GitHub account

Chat and Agent sessions with a LithosAI model work without a GitHub sign-in or a Copilot plan. Without a sign-in, VS Code has no model for background tasks such as chat titles and commit messages, and it shows Set BYOK utility models in the Chat view. Setting utility models is optional. To enable those tasks, open Settings and select your LithosAI model for chat.utilityModel and chat.utilitySmallModel. VS Code recommends a fast, inexpensive model for chat.utilitySmallModel. Each background task is a separate LithosAI request. Inline suggestions (code completions) and semantic search still require a GitHub account.

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Limitations

  • The Copilot session target and the Agents window don’t list LithosAI models by default. To use them there, enable chat.agentHost.byokModels.enabled, which VS Code marks as experimental.
  • On Copilot Business or Enterprise, your administrator can disable the Bring Your Own Language Model Key in VS Code policy. You then can’t add LithosAI models.
Issues common to every agent are listed under Common issues.

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