# AgentCore Runtime versioning and endpoints
<a name="agent-runtime-versioning"></a>

Amazon Bedrock AgentCore implements automatic versioning for AgentCore Runtimes and lets you manage different configurations using endpoints.

Each AgentCore Runtime in Amazon Bedrock AgentCore is automatically versioned:
+ When you create an AgentCore Runtime, AgentCore Runtime automatically creates version 1 (V1)
+ Each update to the AgentCore Runtime creates a new version with a complete, self-contained configuration
+ Versions are immutable once created
+ Each version contains all the configuration needed for execution

## How endpoints reference versions
<a name="endpoint-versioning"></a>

Endpoints provide a way to reference specific versions of your AgentCore Runtime:
+ The `DEFAULT` endpoint automatically points to the latest version of your AgentCore Runtime
+ Endpoints can point to specific versions, allowing you to maintain different environments (e.g., development, staging, production)
+ When you update an AgentCore Runtime, the `DEFAULT` endpoint is automatically updated to point to the new version
+ Endpoints must be explicitly updated to point to new versions

 **Example Updating an endpoint to a New Version** 

```
bedrock_agentcore_client = boto3.client('bedrock-agentcore', region_name='us-west-2')

response = bedrock_agentcore_client.update_agent_runtime_endpoint(
    agentRuntimeId='agent-runtime-12345',
    endpointName='production-endpoint',
    agentRuntimeVersion='v2.1',
    description='Updated production endpoint'
)

print(response)
```

## Versioning scenarios
<a name="versioning-scenarios"></a>

The following table illustrates how versioning and endpoints interact during the lifecycle of an AgentCore Runtime:


| Change Type | Version Creation Behavior | Latest Version | Endpoint Behavior | 
| --- | --- | --- | --- | 
|  Initial Creation  |  Creates Version 1 (V1) automatically  |  V1  |  DEFAULT points to V1  | 
|  Protocol Change  |  Creates a new version with updated protocol settings  |  V2  |  DEFAULT automatically updates to V2  | 
|  Create "PROD" endpoint with V2  |  No new version created  |  V2  |  PROD endpoint points to V2  | 
|  Container Image Update  |  Creates a new version with new container reference  |  V3  |  DEFAULT updates to V3, PROD remains on V2  | 
|  Update "PROD" to V3  |  No new version created  |  V3  |  PROD updates to V3  | 
|  Network Settings Modification  |  Creates a new version with updated security parameters  |  V4  |  DEFAULT updates to V4, PROD remains on V3  | 

## Endpoint lifecycle states
<a name="endpoint-lifecycle"></a>

AgentCore Runtime endpoints go through various states during their lifecycle:

CREATING  
Initial state when an endpoint is being created

CREATE\$1FAILED  
Indicates creation failure due to permissions, container, or other issues

READY  
Endpoint is ready to accept requests

UPDATING  
Endpoint is being updated to a new version

UPDATE\$1FAILED  
Indicates update operation failure

## Listing AgentCore Runtime versions and endpoints
<a name="listing-versions"></a>

You can list all versions of an AgentCore Runtime by calling the `ListAgentRuntimeVersions` operation. To list the endpoints for an AgentCore Runtime, call `ListAgentRuntimeEndpoints`.