Invoke Amazon Titan Text models on Amazon Bedrock using the Invoke Model API - Amazon Bedrock

Invoke Amazon Titan Text models on Amazon Bedrock using the Invoke Model API

The following code examples show how to send a text message to Amazon Titan Text, using the Invoke Model API.

.NET
AWS SDK for .NET
Note

There's more on GitHub. Find the complete example and learn how to set up and run in the AWS Code Examples Repository.

Use the Invoke Model API to send a text message.

// Use the native inference API to send a text message to Amazon Titan Text. using System; using System.IO; using System.Text.Json; using System.Text.Json.Nodes; using Amazon; using Amazon.BedrockRuntime; using Amazon.BedrockRuntime.Model; // Create a Bedrock Runtime client in the AWS Region you want to use. var client = new AmazonBedrockRuntimeClient(RegionEndpoint.USEast1); // Set the model ID, e.g., Titan Text Premier. var modelId = "amazon.titan-text-premier-v1:0"; // Define the user message. var userMessage = "Describe the purpose of a 'hello world' program in one line."; //Format the request payload using the model's native structure. var nativeRequest = JsonSerializer.Serialize(new { inputText = userMessage, textGenerationConfig = new { maxTokenCount = 512, temperature = 0.5 } }); // Create a request with the model ID and the model's native request payload. var request = new InvokeModelRequest() { ModelId = modelId, Body = new MemoryStream(System.Text.Encoding.UTF8.GetBytes(nativeRequest)), ContentType = "application/json" }; try { // Send the request to the Bedrock Runtime and wait for the response. var response = await client.InvokeModelAsync(request); // Decode the response body. var modelResponse = await JsonNode.ParseAsync(response.Body); // Extract and print the response text. var responseText = modelResponse["results"]?[0]?["outputText"] ?? ""; Console.WriteLine(responseText); } catch (AmazonBedrockRuntimeException e) { Console.WriteLine($"ERROR: Can't invoke '{modelId}'. Reason: {e.Message}"); throw; }
  • For API details, see InvokeModel in AWS SDK for .NET API Reference.

Go
SDK for Go V2
Note

There's more on GitHub. Find the complete example and learn how to set up and run in the AWS Code Examples Repository.

Use the Invoke Model API to send a text message.

// Each model provider has their own individual request and response formats. // For the format, ranges, and default values for Amazon Titan Text, refer to: // https://docs.aws.amazon.com/bedrock/latest/userguide/model-parameters-titan-text.html type TitanTextRequest struct { InputText string `json:"inputText"` TextGenerationConfig TextGenerationConfig `json:"textGenerationConfig"` } type TextGenerationConfig struct { Temperature float64 `json:"temperature"` TopP float64 `json:"topP"` MaxTokenCount int `json:"maxTokenCount"` StopSequences []string `json:"stopSequences,omitempty"` } type TitanTextResponse struct { InputTextTokenCount int `json:"inputTextTokenCount"` Results []Result `json:"results"` } type Result struct { TokenCount int `json:"tokenCount"` OutputText string `json:"outputText"` CompletionReason string `json:"completionReason"` } func (wrapper InvokeModelWrapper) InvokeTitanText(ctx context.Context, prompt string) (string, error) { modelId := "amazon.titan-text-express-v1" body, err := json.Marshal(TitanTextRequest{ InputText: prompt, TextGenerationConfig: TextGenerationConfig{ Temperature: 0, TopP: 1, MaxTokenCount: 4096, }, }) if err != nil { log.Fatal("failed to marshal", err) } output, err := wrapper.BedrockRuntimeClient.InvokeModel(ctx, &bedrockruntime.InvokeModelInput{ ModelId: aws.String(modelId), ContentType: aws.String("application/json"), Body: body, }) if err != nil { ProcessError(err, modelId) } var response TitanTextResponse if err := json.Unmarshal(output.Body, &response); err != nil { log.Fatal("failed to unmarshal", err) } return response.Results[0].OutputText, nil }
  • For API details, see InvokeModel in AWS SDK for Go API Reference.

Java
SDK for Java 2.x
Note

There's more on GitHub. Find the complete example and learn how to set up and run in the AWS Code Examples Repository.

Use the Invoke Model API to send a text message.

// Use the native inference API to send a text message to Amazon Titan Text. import org.json.JSONObject; import org.json.JSONPointer; import software.amazon.awssdk.auth.credentials.DefaultCredentialsProvider; import software.amazon.awssdk.core.SdkBytes; import software.amazon.awssdk.core.exception.SdkClientException; import software.amazon.awssdk.regions.Region; import software.amazon.awssdk.services.bedrockruntime.BedrockRuntimeClient; public class InvokeModel { public static String invokeModel() { // Create a Bedrock Runtime client in the AWS Region you want to use. // Replace the DefaultCredentialsProvider with your preferred credentials provider. var client = BedrockRuntimeClient.builder() .credentialsProvider(DefaultCredentialsProvider.create()) .region(Region.US_EAST_1) .build(); // Set the model ID, e.g., Titan Text Premier. var modelId = "amazon.titan-text-premier-v1:0"; // The InvokeModel API uses the model's native payload. // Learn more about the available inference parameters and response fields at: // https://docs.aws.amazon.com/bedrock/latest/userguide/model-parameters-titan-text.html var nativeRequestTemplate = "{ \"inputText\": \"{{prompt}}\" }"; // Define the prompt for the model. var prompt = "Describe the purpose of a 'hello world' program in one line."; // Embed the prompt in the model's native request payload. String nativeRequest = nativeRequestTemplate.replace("{{prompt}}", prompt); try { // Encode and send the request to the Bedrock Runtime. var response = client.invokeModel(request -> request .body(SdkBytes.fromUtf8String(nativeRequest)) .modelId(modelId) ); // Decode the response body. var responseBody = new JSONObject(response.body().asUtf8String()); // Retrieve the generated text from the model's response. var text = new JSONPointer("/results/0/outputText").queryFrom(responseBody).toString(); System.out.println(text); return text; } catch (SdkClientException e) { System.err.printf("ERROR: Can't invoke '%s'. Reason: %s", modelId, e.getMessage()); throw new RuntimeException(e); } } public static void main(String[] args) { invokeModel(); } }
  • For API details, see InvokeModel in AWS SDK for Java 2.x API Reference.

JavaScript
SDK for JavaScript (v3)
Note

There's more on GitHub. Find the complete example and learn how to set up and run in the AWS Code Examples Repository.

Use the Invoke Model API to send a text message.

import { fileURLToPath } from "url"; import { FoundationModels } from "../../config/foundation_models.js"; import { BedrockRuntimeClient, InvokeModelCommand, } from "@aws-sdk/client-bedrock-runtime"; /** * @typedef {Object} ResponseBody * @property {Object[]} results */ /** * Invokes an Amazon Titan Text generation model. * * @param {string} prompt - The input text prompt for the model to complete. * @param {string} [modelId] - The ID of the model to use. Defaults to "amazon.titan-text-express-v1". */ export const invokeModel = async ( prompt, modelId = "amazon.titan-text-express-v1", ) => { // Create a new Bedrock Runtime client instance. const client = new BedrockRuntimeClient({ region: "us-east-1" }); // Prepare the payload for the model. const payload = { inputText: prompt, textGenerationConfig: { maxTokenCount: 4096, stopSequences: [], temperature: 0, topP: 1, }, }; // Invoke the model with the payload and wait for the response. const command = new InvokeModelCommand({ contentType: "application/json", body: JSON.stringify(payload), modelId, }); const apiResponse = await client.send(command); // Decode and return the response. const decodedResponseBody = new TextDecoder().decode(apiResponse.body); /** @type {ResponseBody} */ const responseBody = JSON.parse(decodedResponseBody); return responseBody.results[0].outputText; }; // Invoke the function if this file was run directly. if (process.argv[1] === fileURLToPath(import.meta.url)) { const prompt = 'Complete the following in one sentence: "Once upon a time..."'; const modelId = FoundationModels.TITAN_TEXT_G1_EXPRESS.modelId; console.log(`Prompt: ${prompt}`); console.log(`Model ID: ${modelId}`); try { console.log("-".repeat(53)); const response = await invokeModel(prompt, modelId); console.log(response); } catch (err) { console.log(err); } }
  • For API details, see InvokeModel in AWS SDK for JavaScript API Reference.

Python
SDK for Python (Boto3)
Note

There's more on GitHub. Find the complete example and learn how to set up and run in the AWS Code Examples Repository.

Use the Invoke Model API to send a text message.

# Use the native inference API to send a text message to Amazon Titan Text. import boto3 import json from botocore.exceptions import ClientError # Create a Bedrock Runtime client in the AWS Region of your choice. client = boto3.client("bedrock-runtime", region_name="us-east-1") # Set the model ID, e.g., Titan Text Premier. model_id = "amazon.titan-text-premier-v1:0" # Define the prompt for the model. prompt = "Describe the purpose of a 'hello world' program in one line." # Format the request payload using the model's native structure. native_request = { "inputText": prompt, "textGenerationConfig": { "maxTokenCount": 512, "temperature": 0.5, }, } # Convert the native request to JSON. request = json.dumps(native_request) try: # Invoke the model with the request. response = client.invoke_model(modelId=model_id, body=request) except (ClientError, Exception) as e: print(f"ERROR: Can't invoke '{model_id}'. Reason: {e}") exit(1) # Decode the response body. model_response = json.loads(response["body"].read()) # Extract and print the response text. response_text = model_response["results"][0]["outputText"] print(response_text)
  • For API details, see InvokeModel in AWS SDK for Python (Boto3) API Reference.

For a complete list of AWS SDK developer guides and code examples, see Using Amazon Bedrock with an AWS SDK. This topic also includes information about getting started and details about previous SDK versions.