Method createMessage

src/api/providers/anthropic.ts:51–354

(
		systemPrompt: string,
		messages: Anthropic.Messages.MessageParam[],
		metadata?: ApiHandlerCreateMessageMetadata,
	)

	}

	async *createMessage(
		systemPrompt: string,
		messages: Anthropic.Messages.MessageParam[],
		metadata?: ApiHandlerCreateMessageMetadata,
	): ApiStream {
		let stream: AnthropicStream<Anthropic.Messages.RawMessageStreamEvent>
		const cacheControl: CacheControlEphemeral = { type: "ephemeral" }
		const {
			id: modelId,
			betas = ["fine-grained-tool-streaming-2025-05-14"],
			maxTokens,
			temperature,
			info,
			reasoningBudget,
		} = this.getModel()
		const thinking = getAnthropicProviderReasoning({
			model: info,
			reasoningBudget,
			settings: this.options,
		})

		// Filter out non-Anthropic blocks (reasoning, thoughtSignature, etc.) before sending to the API
		const sanitizedMessages = filterNonAnthropicBlocks(messages)

		// Add 1M context beta flag if enabled for supported models (Claude Sonnet 4/4.5/4.6, Opus 4.6)
		if (
			(modelId === "claude-sonnet-4-20250514" ||
				modelId === "claude-sonnet-4-5" ||
				modelId === "claude-sonnet-4-6" ||
				modelId === "claude-opus-4-6") &&
			this.options.anthropicBeta1MContext
		) {
			betas.push("context-1m-2025-08-07")
		}

		const nativeToolParams = {
			tools: convertOpenAIToolsToAnthropic(metadata?.tools ?? []),
			tool_choice: convertOpenAIToolChoiceToAnthropic(metadata?.tool_choice, metadata?.parallelToolCalls),
		}

		switch (modelId) {
			case "claude-sonnet-5":
			case "claude-sonnet-4-6":
			case "claude-sonnet-4-5":
			case "claude-sonnet-4-20250514":
			case "claude-opus-4-6":
			case "claude-opus-4-7":
			case "claude-opus-4-8":
			case "claude-fable-5":
			case "claude-opus-4-5-20251101":
			case "claude-opus-4-1-20250805":
			case "claude-opus-4-20250514":
			case "claude-3-7-sonnet-20250219":
			case "claude-3-5-sonnet-20241022":
			case "claude-3-5-haiku-20241022":
			case "claude-3-opus-20240229":
			case "claude-haiku-4-5-20251001":
			case "claude-3-haiku-20240307": {