diff --git a/docs/references/sdk-metrics.mdx b/docs/references/sdk-metrics.mdx
index 4726ecab4b..e3c24290db 100644
--- a/docs/references/sdk-metrics.mdx
+++ b/docs/references/sdk-metrics.mdx
@@ -543,6 +543,7 @@ Valid values for the `failure_reason` tag:
 
 - `NonDeterminismError`: The Workflow Task failed due to a non-determinism error.
 - `GrpcMessageTooLarge`: The Workflow Task response exceeded the gRPC message size limit and could not be delivered. The Temporal Service terminates the Workflow Execution in response. See [Troubleshoot the BlobSizeLimitError](/troubleshooting/blob-size-limit-error).
+- `PayloadsTooLarge`: A Payload or Memo in the Workflow Task response exceeded the Namespace size limit, so the Worker proactively failed the Workflow Task as retryable. See [Troubleshoot the BlobSizeLimitError](/troubleshooting/blob-size-limit-error#payload-size-limit).
 - `WorkflowError`: The Workflow Task failed for any other reason.
 
 ### `workflow_task_execution_latency`