# Update evaluator
<a name="update-evaluator"></a>

The `UpdateEvaluator` API modifies an existing custom evaluator’s configuration, description, or evaluation level. This asynchronous operation is only allowed on unlocked evaluators.

 **Modification lock protection:** Updates are not allowed if the evaluator has been used by any enabled evaluation configuration.

 **Rating scale changes:** You can change `ratingScale` between `numerical`, `categorical`, and `multiDimensional`, and add, remove, or edit dimensions of a [multi-dimension evaluator](multi-dimension-evaluators.md). A new multi-dimension scale is validated the same way as on create. If you change the evaluation `level` without resending `ratingScale`, the stored dimension instructions are checked against the new level’s placeholders.

The API returns immediately with updated metadata. Monitor the evaluator status to confirm changes are applied successfully using the `GetEvaluator` API.

**Topics**
+ [Code samples for AgentCore CLI, AgentCore SDK, and AWS SDK](#update-evaluators-code-samples)
+ [Console](#update-evaluator-console)

## Code samples for AgentCore CLI, AgentCore SDK, and AWS SDK
<a name="update-evaluators-code-samples"></a>

The following code samples demonstrate how to update evaluators using different development approaches. Choose the method that best fits your development environment and preferences.

**Example**  

1. 

   If you created the evaluator with `agentcore add evaluator`, change it in the `evaluators` array in `agentcore/agentcore.json` and run `agentcore deploy`.

   For an evaluator you created outside a project, update it by ID. Run `agentcore eval evaluator list` to find the evaluator ID.

   ```
   agentcore eval evaluator llm-as-a-judge update \
     --id <EVALUATOR_ID> \
     --instructions file://updated-instructions.txt \
     --rating-scale 1-5-quality
   ```
**Note**  
If the evaluator is locked by a running online evaluation, pause that configuration first, or clone the evaluator instead. For a configuration you added with `agentcore add online-eval`, set `enableOnCreate` to `false` in `agentcore/agentcore.json` and run `agentcore deploy`. For a configuration created outside a project, run `agentcore eval online-eval pause --id <ONLINE_EVAL_ID>`, and resume it later with `agentcore eval online-eval resume --id <ONLINE_EVAL_ID>`.

1. 

   ```
   from bedrock_agentcore_starter_toolkit import Evaluation
   
   eval_client = Evaluation()
   
   eval_client.update_evaluator(
           evaluator_id=evaluator_id,
           description="Updated custom evaluator description"
       )
   ```

1. 

   ```
   import boto3
   
   client = boto3.client('bedrock-agentcore-control')
   
   list_configs_response = client.update_evaluator(
       evaluatorId=evaluator_id,
       description="Updated custom evaluator description"
   )
   ```

1. 

   ```
   aws bedrock-agentcore-control update-evaluator \
       --evaluator-id 'evaluator-abc123' \
       --description "Updated custom evaluator description"
   ```

## Console
<a name="update-evaluator-console"></a>

Modify your custom evaluator settings using the console’s editing interface, which provides form validation and guided configuration options.

 **To update a custom evaluator** 

1. Open the Amazon Bedrock AgentCore console.

1. In the navigation pane, under **Resources**, choose **Evaluations**.

1. Choose **Custom evaluators** next to Evaluation configurations.

1. In the **Custom evaluators** card, view the table that lists the custom evaluators you have created.

1. Choose one of the following methods to update the custom evaluator:
   + Choose the custom evaluator name to view its details, then choose **Edit** in the upper right of the details page.
   + Select the custom evaluator so that it is highlighted, then choose **Edit** at the top of the Custom evaluators card.
**Note**  
If the evaluator is in use in any online evaluation, it cannot be updated. Instead, you can duplicate the evaluator and update the cloned version.

1. Update the fields as needed.

1. Choose **Update evaluator** to save the changes.