Function createCodebuffBackendModel

sdk/src/impl/model-provider.ts:198–264

* Create a model that routes through the Codebuff backend. * This is the existing behavior - requests go to Codebuff backend which forwards to OpenRouter.

(
  apiKey: string,
  model: string,
)

 * This is the existing behavior - requests go to Codebuff backend which forwards to OpenRouter.
 */
function createCodebuffBackendModel(
  apiKey: string,
  model: string,
): LanguageModel {
  const openrouterUsage: OpenRouterUsageAccounting = {
    cost: null,
    costDetails: {
      upstreamInferenceCost: null,
    },
  }

  const openrouterApiKey = getByokOpenrouterApiKeyFromEnv()

  return new OpenAICompatibleChatLanguageModel(model, {
    provider: 'codebuff',
    url: ({ path: endpoint }) =>
      new URL(path.join('/api/v1', endpoint), WEBSITE_URL).toString(),
    headers: () => ({
      Authorization: `Bearer ${apiKey}`,
      'user-agent': `ai-sdk/openai-compatible/${VERSION}/codebuff`,
      ...(openrouterApiKey && { [BYOK_OPENROUTER_HEADER]: openrouterApiKey }),
    }),
    metadataExtractor: {
      extractMetadata: async ({ parsedBody }: { parsedBody: any }) => {
        if (openrouterApiKey !== undefined) {
          return { codebuff: { usage: openrouterUsage } }
        }

        if (typeof parsedBody?.usage?.cost === 'number') {
          openrouterUsage.cost = parsedBody.usage.cost
        }
        if (
          typeof parsedBody?.usage?.cost_details?.upstream_inference_cost ===
          'number'
        ) {
          openrouterUsage.costDetails.upstreamInferenceCost =
            parsedBody.usage.cost_details.upstream_inference_cost
        }
        return { codebuff: { usage: openrouterUsage } }
      },
      createStreamExtractor: () => ({
        processChunk: (parsedChunk: any) => {
          if (openrouterApiKey !== undefined) {
            return
          }

          if (typeof parsedChunk?.usage?.cost === 'number') {
            openrouterUsage.cost = parsedChunk.usage.cost
          }
          if (
            typeof parsedChunk?.usage?.cost_details?.upstream_inference_cost ===
            'number'
          ) {
            openrouterUsage.costDetails.upstreamInferenceCost =
              parsedChunk.usage.cost_details.upstream_inference_cost
          }
        },
        buildMetadata: () => {