Document workflow termination for gRPC message size limit errors (#4009)

Co-authored-by: promptless[bot] <179508745+promptless[bot]@users.noreply.github.com>
Co-authored-by: Lenny Chen <55669665+lennessyy@users.noreply.github.com>

Author: promptless[bot]

docs/references/errors.mdx

@@ -192,6 +192,18 @@ A retry will be scheduled if the error is recoverable.
 
 {/* TODO: more info */}
 
+## gRPC Message Too Large {#grpc-message-too-large}
+
+This error occurs when the Workflow Task response exceeds the gRPC message size limit of 4 MB.
+The Workflow Execution is automatically terminated because this is a non-recoverable error.
+
+This typically happens when a Workflow schedules too many Activities, Child Workflows, or commands in a single Workflow Task, or when a Workflow returns a large result.
+
+To resolve this error, fix your Workflow code and start a new Workflow Execution.
+Break work into smaller batches, reduce the size of Workflow returns, use Continue-As-New for long-running Workflows, or compress large payloads with a custom Payload Codec.
+
+See the [BlobSizeLimitError troubleshooting guide](/troubleshooting/blob-size-limit-error) for detailed resolution strategies.
+
 ## Nondeterminism Error {#non-deterministic-error}
 
 The [Workflow Task](/tasks#workflow-task) failed due to a [nondeterminism error](/workflow-definition#non-deterministic-change).

docs/troubleshooting/blob-size-limit-error.mdx

@@ -45,3 +45,15 @@ There are multiple strategies you can use to avoid this error:
 3. Consider offloading large payloads to an object store to reduce the risk of exceeding blob size limits:
    1. Pass references to the stored payloads within the Workflow instead of the actual data.
    2. Retrieve the payloads from the object store when needed during execution.
+
+## Workflow termination due to oversized response
+
+When a Workflow Task response exceeds the 4 MB gRPC message size limit, Temporal automatically terminates the Workflow Execution. This is a non-recoverable error. The Workflow can't progress if it generates a response that's too large, so retrying won't help.
+
+This typically happens when a Workflow schedules too many Activities, Child Workflows, or other commands in a single Workflow Task. The total size of all commands generated by the Workflow Task must fit within the 4 MB limit.
+
+If your Workflow was terminated for this reason, you'll see a `WorkflowExecutionTerminated` event in the Event History with the cause `WORKFLOW_TASK_FAILED_CAUSE_GRPC_MESSAGE_TOO_LARGE`.
+
+To prevent this, use the batching strategies described above to split work across multiple Workflow Tasks instead of scheduling everything at once.
+
+See the [gRPC Message Too Large error reference](/references/errors#grpc-message-too-large) for more details.