When using Anthropic in a bring your own key configuration…

Error message

When using Anthropic in a bring your own key configuration, you must provide a valid token

What it means

buildClient() throws this when the model kind is Anthropic in bring-your-own-key mode but no Anthropic API key is configured (getAnthropicKey() returned empty). AnthropicAIClient needs the key for authentication.

Solutions

Enter a valid Anthropic API key in the AI settings.
Create a key at console.anthropic.com if needed.
Or switch to another provider (local model or GitButler API).

Example fix

// before
anthropicKey: ''
// after
anthropicKey: 'sk-ant-...' // valid Anthropic API key

Defensive patterns

Strategy: validation

Validate before calling

const key = await aiService.getAnthropicKey();
if (!key) {
  // prompt for the Anthropic API key before invoking AI features
}

Try / catch

try {
  await aiService.summarize(...);
} catch (e) {
  if (e.message.includes('Anthropic') && e.message.includes('valid token')) {
    // open settings to collect the Anthropic API key
  } else {
    throw e;
  }
}

Prevention

Enter the Anthropic API key when selecting the Anthropic provider.
Validate key format (starts with 'sk-ant-') on save.
Re-enter the key after settings resets or reinstalls.

When it happens

Trigger: User selects Anthropic as the AI provider without entering an API key in settings.

Common situations: Chose Anthropic but never filled the key; key lost after settings reset or app reinstall; key field left blank because the user expected bundled credentials.

Understand the failure class

Background: "API key is required" / "API key not found" / "No API key was set": the missing-api-key error family across 16 libraries — this error's family across 16 libraries.

Related errors

AI-assisted analysis of gitbutlerapp/gitbutler@58e5313667 (2026-09-18). Data as JSON: /api/errors/9205e168c20d9138. Report an issue: GitHub.

Appendix: source

Thrown at apps/desktop/src/lib/ai/service.ts:356

			const openAIModelName = await this.getOpenAIModelName();
			const openAIKey = await this.getOpenAIKey();
			const openAICustomEndpoint = await this.getOpenAICustomEndpoint();

			if (!openAIKey) {
				throw new Error(
					"When using OpenAI in a bring your own key configuration, you must provide a valid token",
				);
			}

			return new OpenAIClient(openAIKey, openAIModelName, openAICustomEndpoint);
		}

		if (modelKind === ModelKind.Anthropic) {
			const anthropicModelName = await this.getAnthropicModelName();
			const anthropicKey = await this.getAnthropicKey();

			if (!anthropicKey) {
				throw new Error(
					"When using Anthropic in a bring your own key configuration, you must provide a valid token",
				);
			}

			return new AnthropicAIClient(anthropicKey, anthropicModelName);
		}

		if (modelKind === ModelKind.OpenRouter) {
			const openRouterKey = (await this.getOpenRouterKey())?.trim();
			const openRouterModelName = await this.getOpenRouterModelName();

			if (!openRouterKey) {
				throw new Error("When using OpenRouter, you must provide a valid API key");
			}

			return new OpenAIClient(openRouterKey, openRouterModelName, "https://openrouter.ai/api/v1");
		}

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