Class OpencodeGoHandler

src/api/providers/opencode-go.ts:69–546

 * and non-streaming prompt completion.
 */
export class OpencodeGoHandler extends RouterProvider implements SingleCompletionHandler {
	/**
	 * Anthropic SDK client used for Go models that only accept the Anthropic
	 * Messages wire format (`/v1/messages`).
	 *
	 * The SDK appends `/v1/messages` to `baseURL`, so this is set to the Go
	 * gateway root (`https://opencode.ai/zen/go`) — NOT the `/v1` root used by
	 * the OpenAI client — to avoid a doubled `/v1` path segment.
	 */
	private readonly anthropicClient: Anthropic

	/** Creates a new handler bound to the user's Go API key and selected model. */
	constructor(options: ApiHandlerOptions) {
		super({
			options,
			name: "opencode-go",
			baseURL: "https://opencode.ai/zen/go/v1",
			apiKey: options.opencodeGoApiKey,
			modelId: options.opencodeGoModelId,
			defaultModelId: opencodeGoDefaultModelId,
			defaultModelInfo: opencodeGoDefaultModelInfo,
		})

		this.anthropicClient = new Anthropic({
			baseURL: "https://opencode.ai/zen/go",
			apiKey: options.opencodeGoApiKey,
			defaultHeaders: {
				...DEFAULT_HEADERS,
				...(options.openAiHeaders || {}),
			},
		})
	}

	/**
	 * Resolves the configured model and computes model parameters
	 * (max tokens, temperature, reasoning effort) from the merged model info.
	 *
	 * The wire format is derived from the model ID via
	 * {@link isOpencodeGoAnthropicFormatModel}: Anthropic-format models compute
	 * parameters with the `anthropic` format so reasoning is mapped to the
	 * Anthropic-style controls; everything else uses the `openai` format.
	 *
	 * Fetches the live model list first so the merged native + `/models`
	 * metadata (context window, capability flags, pricing) is available before
	 * parameter computation — mirroring the original `fetchModel()` flow.
	 */
	private async resolveModel() {
		const { id, info } = await this.fetchModel()
		const isAnthropic = isOpencodeGoAnthropicFormatModel(id)
		// getModelParams is overloaded on a literal `format`, so branch the call
		// rather than passing a union — this keeps the returned params typed as a
		// single concrete shape per branch.
		const params = isAnthropic
			? getModelParams({
					format: "anthropic",
					modelId: id,
					model: info,
					settings: this.options,