Call Amazon Bedrock with Step Functions

Step Functions can control certain Amazon services directly from Amazon States Language (ASL). To learn more, see Working with other services and Pass parameters to a service API.

Amazon Bedrock service integration APIs

To integrate Amazon Step Functions with Amazon Bedrock, you can use the following APIs. These APIs are similar to the corresponding Amazon Bedrock APIs, with some differences in the request fields that are passed.

The following table describes the differences between each service integration API and its corresponding Amazon Bedrock API.

{
    "ModelId": String,  // required
    "Accept": String,  // default: application/json
    "ContentType": String,  // default: application/json
    "Input": {  // not from Bedrock API
        "S3Uri": String
    },  
    "Output": {  // not from Bedrock API
        "S3Uri": String
    } 
}

For information about how to configure IAM permissions when using Step Functions with other Amazon services, see IAM Policies for integrated services.

Task state definition for Amazon Bedrock integration

The following Task state definition shows how you can integrate with Amazon Bedrock in your state machines. This example shows a Task state that extracts the full result of model invocation specified by the path, result_one. This is based on Inference parameters for foundation models. This example uses the Cohere Command large language model (LLM).

{
  "Type": "Task",
  "Resource": "arn:aws:states:::bedrock:invokeModel",
  "Parameters": {
    "ModelId": "cohere.command-text-v14",
    "Body": {
      "prompt.$": "$.prompt_one",
      "max_tokens": 250
    },
    "ContentType": "application/json",
    "Accept": "*/*"
  },
  "ResultPath": "$.result_one",
  "ResultSelector": {
    "result_one.$": "$.Body.generations[0].text"
  },
  "End": true
}