Method structuredOutput

packages/ai-gemini/src/adapters/text.ts:169–223

* Generate structured output using Gemini's native JSON response format. * Uses responseMimeType: 'application/json' and responseSchema for structured output. * The outputSchema is already JSON Schema (converted in the ai layer).

(
    options: StructuredOutputOptions<GeminiTextProviderOptions>,
  )

   * The outputSchema is already JSON Schema (converted in the ai layer).
   */
  async structuredOutput(
    options: StructuredOutputOptions<GeminiTextProviderOptions>,
  ): Promise<StructuredOutputResult<unknown>> {
    const { chatOptions, outputSchema } = options
    const { logger } = chatOptions

    const mappedOptions = this.mapCommonOptionsToGemini(chatOptions)

    try {
      logger.request(
        `activity=chat provider=gemini model=${this.model} messages=${chatOptions.messages.length} tools=${chatOptions.tools?.length ?? 0} stream=false`,
        { provider: 'gemini', model: this.model },
      )
      // Add structured output configuration
      const result = await this.client.models.generateContent({
        ...mappedOptions,
        config: {
          ...mappedOptions.config,
          responseMimeType: 'application/json',
          responseSchema: outputSchema,
        },
      })

      // Extract text content from the response
      const rawText = this.extractTextFromResponse(result)

      // Parse the JSON response
      let parsed: unknown
      try {
        parsed = JSON.parse(rawText)
      } catch {
        throw new Error(
          `Failed to parse structured output as JSON. Content: ${rawText.slice(0, 200)}${rawText.length > 200 ? '...' : ''}`,
        )
      }

      return {
        data: parsed,
        rawText,
        usage: result.usageMetadata
          ? buildGeminiUsage(result.usageMetadata)
          : undefined,
      }
    } catch (error) {
      logger.errors('gemini.structuredOutput fatal', {
        error,
        source: 'gemini.structuredOutput',
      })
      throw new Error(
        error instanceof Error
          ? error.message
          : 'An unknown error occurred during structured output generation.',
      )
    }
  }

  /**
   * Extract text content from a non-streaming response