diff --git a/app/Http/Controllers/Api/WorkerController.php b/app/Http/Controllers/Api/WorkerController.php
index 9f63b4ac5..6c230b67a 100644
--- a/app/Http/Controllers/Api/WorkerController.php
+++ b/app/Http/Controllers/Api/WorkerController.php
@@ -51,7 +51,7 @@
 use App\Support\WorkflowQueryTaskBroker;
 use App\Support\WorkflowReplayEligibility;
 use App\Support\WorkflowStreamCommandProcessor;
-use App\Support\WorkflowStreamService;
+use App\Support\WorkflowTaskCompletionValidation;
 use App\Support\WorkflowTaskLeaseRecovery;
 use App\Support\WorkflowTaskPoller;
 use App\Support\WorkflowUpdateValidationTaskBroker;
@@ -1659,144 +1659,7 @@ private function mutateWorkflowTaskCommands(Request $request, string $taskId, bo
             'message_stream_waits.*.after_position' => ['required', 'integer', 'min:0'],
         ]);
 
-        $completionRules = [
-            'lease_owner' => ['required', 'string'],
-            'workflow_task_attempt' => ['required', 'integer', 'min:1'],
-            'commands' => ['required', 'array', 'min:1'],
-            'commands.*.type' => ['required', 'string'],
-            'commands.*.cancellation_scope_id' => ['sometimes', 'string', 'min:1', 'max:255'],
-            'commands.*.cancellation_cleanup' => ['sometimes', 'required', 'array:scope_id,request_id,delivery_history_event_id'],
-            'commands.*.cancellation_cleanup.scope_id' => ['sometimes', 'required', 'string', 'max:255'],
-            'commands.*.cancellation_cleanup.request_id' => ['required_with:commands.*.cancellation_cleanup', 'string', 'max:255'],
-            'commands.*.cancellation_cleanup.delivery_history_event_id' => ['required_with:commands.*.cancellation_cleanup', 'string', 'max:255'],
-            'commands.*.result' => ['nullable'],
-            'commands.*.activity_type' => ['nullable', 'string'],
-            'commands.*.arguments' => ['nullable'],
-            'commands.*.connection' => ['nullable', 'string'],
-            'commands.*.queue' => ['nullable', 'string'],
-            'commands.*.retry_policy' => ['nullable', 'array'],
-            'commands.*.retry_policy.max_attempts' => ['nullable', 'integer', 'min:1'],
-            'commands.*.retry_policy.backoff_seconds' => ['nullable', 'array'],
-            'commands.*.retry_policy.backoff_seconds.*' => ['integer', 'min:0'],
-            'commands.*.retry_policy.non_retryable_error_types' => ['nullable', 'array'],
-            'commands.*.retry_policy.non_retryable_error_types.*' => ['string'],
-            'commands.*.retry_policy.*' => ['nullable'],
-            'commands.*.start_to_close_timeout' => ['nullable', 'integer', 'min:1'],
-            'commands.*.schedule_to_start_timeout' => ['nullable', 'integer', 'min:1'],
-            'commands.*.schedule_to_close_timeout' => ['nullable', 'integer', 'min:1'],
-            'commands.*.heartbeat_timeout' => ['nullable', 'integer', 'min:1'],
-            'commands.*.execution_mode' => ['nullable', 'string', 'in:local'],
-            'commands.*.outcome' => ['nullable', 'string', 'in:completed,failed,timed_out,cancelled'],
-            'commands.*.attempts' => ['nullable', 'array', 'max:100'],
-            'commands.*.attempts.*.attempt_id' => ['nullable', 'string', 'max:255'],
-            'commands.*.attempts.*.attempt_number' => ['required', 'integer', 'min:1'],
-            'commands.*.attempts.*.outcome' => ['required', 'string', 'in:completed,failed,timed_out,cancelled'],
-            'commands.*.attempts.*.duration_ms' => ['nullable', 'integer', 'min:0'],
-            'commands.*.attempts.*.message' => ['nullable', 'string'],
-            'commands.*.attempts.*.exception_type' => ['nullable', 'string', 'max:255'],
-            'commands.*.attempts.*.non_retryable' => ['nullable', 'boolean'],
-            'commands.*.attempts.*.timeout_kind' => ['nullable', 'string', 'in:start_to_close,schedule_to_close,heartbeat'],
-            'commands.*.attempts.*.retry_reason' => ['nullable', 'string', 'in:failure,timeout,cold_replay'],
-            'commands.*.attempts.*.backoff_seconds' => ['nullable', 'integer', 'min:0'],
-            'commands.*.attempts.*.heartbeats' => ['nullable', 'array', 'max:1000'],
-            'commands.*.attempts.*.heartbeats.*.details' => ['nullable', 'array'],
-            'commands.*.attempts.*.heartbeats.*.elapsed_ms' => ['nullable', 'integer', 'min:0'],
-            'commands.*.attempts.*.heartbeats.*.*' => ['nullable'],
-            'commands.*.attempts.*.*' => ['nullable'],
-            'commands.*.worker_session' => ['nullable', 'array'],
-            'commands.*.worker_session.session_id' => ['nullable', 'string', 'max:255'],
-            'commands.*.worker_session.connection' => ['nullable', 'string', 'max:255'],
-            'commands.*.worker_session.queue' => ['nullable', 'string', 'max:255'],
-            'commands.*.worker_session.requirements' => ['nullable', 'array'],
-            'commands.*.worker_session.requirements.*' => ['string', 'max:255'],
-            'commands.*.worker_session.lease_seconds' => ['nullable', 'integer', 'min:1'],
-            'commands.*.worker_session.ttl_seconds' => ['nullable', 'integer', 'min:1'],
-            'commands.*.worker_session.max_concurrent_activities' => ['nullable', 'integer', 'min:1'],
-            'commands.*.worker_session.create_if_missing' => ['nullable', 'boolean'],
-            'commands.*.worker_session.allow_reacquire_after_failure' => ['nullable', 'boolean'],
-            'commands.*.execution_timeout_seconds' => ['nullable', 'integer', 'min:1'],
-            'commands.*.run_timeout_seconds' => ['nullable', 'integer', 'min:1'],
-            'commands.*.workflow_type' => ['nullable', 'string'],
-            'commands.*.delay_seconds' => ['nullable', 'integer', 'min:0'],
-            'commands.*.message' => ['nullable', 'string'],
-            'commands.*.timeout_kind' => ['nullable', 'string', 'in:start_to_close,schedule_to_close,heartbeat'],
-            'commands.*.payload_codec' => ['nullable', 'string'],
-            'commands.*.update_id' => ['nullable', 'string'],
-            'commands.*.exception_class' => ['nullable', 'string'],
-            'commands.*.exception_type' => ['nullable', 'string'],
-            'commands.*.exception' => ['nullable', 'array'],
-            'commands.*.failed_step_sequence' => ['nullable', 'integer', 'min:1'],
-            'commands.*.failed_activity_execution_id' => ['nullable', 'string', 'max:255'],
-            'commands.*.change_id' => ['nullable', 'string'],
-            'commands.*.version' => ['nullable', 'integer'],
-            'commands.*.min_supported' => ['nullable', 'integer'],
-            'commands.*.max_supported' => ['nullable', 'integer'],
-            'commands.*.attributes' => ['nullable', 'array'],
-            'commands.*.attribute_types' => ['nullable', 'array'],
-            'commands.*.attribute_types.*' => ['string'],
-            'commands.*.entries' => ['nullable', 'array'],
-            'commands.*.non_retryable' => ['nullable', 'boolean'],
-            'commands.*.parent_close_policy' => ['nullable', 'string'],
-            'commands.*.cancellation_policy' => ['nullable', 'string', 'in:try_cancel,wait_cancellation_completed,abandon'],
-            'commands.*.condition_key' => ['nullable', 'string'],
-            'commands.*.condition_definition_fingerprint' => ['nullable', 'string'],
-            'commands.*.condition_wait_occurrence_id' => ['nullable', 'string'],
-            'commands.*.signal_name' => ['nullable', 'string'],
-            'commands.*.timeout_seconds' => ['nullable', 'integer', 'min:0'],
-            'commands.*.endpoint_name' => ['nullable', 'string', 'max:191'],
-            'commands.*.service_name' => ['nullable', 'string', 'max:191'],
-            'commands.*.operation_name' => ['nullable', 'string', 'max:191'],
-            'commands.*.request_payload' => ['nullable'],
-            'commands.*.namespace' => ['nullable', 'string', 'max:191'],
-            'commands.*.caller_namespace' => ['nullable', 'string', 'max:191'],
-            'commands.*.service_call_id' => ['nullable', 'string', 'max:191'],
-            'commands.*.idempotency_key' => ['nullable', 'string', 'max:191'],
-            'commands.*.mode_override' => ['nullable', 'string', 'in:sync,async'],
-            'commands.*.wait_for' => ['nullable', 'string', 'in:accepted,completed'],
-            'commands.*.wait_timeout_seconds' => ['nullable', 'integer', 'min:0'],
-            'commands.*.target_workflow_instance_id' => ['nullable', 'string', 'max:191'],
-            'commands.*.target_workflow_run_id' => ['nullable', 'string', 'max:191'],
-            'commands.*.business_key' => ['nullable', 'string', 'max:191'],
-            'commands.*.labels' => ['nullable', 'array'],
-            'commands.*.memo' => ['nullable', 'array'],
-            'commands.*.search_attributes' => ['nullable', 'array'],
-            'commands.*.duplicate_start_policy' => ['nullable', 'string', 'in:reject_duplicate,return_existing_active'],
-            'commands.*.metadata' => ['nullable', 'array'],
-            'commands.*.request_payload_reference' => ['nullable', 'string', 'max:191'],
-            'commands.*.principal_subject' => ['prohibited'],
-            'commands.*.principal_method' => ['prohibited'],
-            'commands.*.principal_roles' => ['prohibited'],
-            'commands.*.principal_tenant' => ['prohibited'],
-            'commands.*.principal_claims' => ['prohibited'],
-            ...WorkflowCommandNormalizer::parallelMetadataValidationRules(),
-            'commands.*.workflow_stream' => ['nullable', 'array'],
-            'commands.*.workflow_stream.operation' => ['required_with:commands.*.workflow_stream', 'string', 'in:append,close,error'],
-            'commands.*.workflow_stream.stream_name' => ['required_with:commands.*.workflow_stream', 'string', 'max:191'],
-            'commands.*.workflow_stream.command_identity' => ['required_with:commands.*.workflow_stream', 'string', 'max:191'],
-            'commands.*.workflow_stream.command_ordinal' => ['required_with:commands.*.workflow_stream', 'integer', 'min:0'],
-            'commands.*.workflow_stream.items' => ['nullable', 'array', 'max:'.WorkflowStreamService::DEFAULT_MAX_ITEMS_PER_APPEND],
-            'commands.*.workflow_stream.items.*' => ['array'],
-            'commands.*.workflow_stream.items.*.payload' => ['nullable'],
-            'commands.*.workflow_stream.items.*.payload_reference' => ['nullable', 'string', 'max:191'],
-            'commands.*.workflow_stream.items.*.payload_codec' => ['nullable', 'string', 'max:64'],
-            'commands.*.workflow_stream.items.*.idempotency_key' => ['nullable', 'string', 'max:191'],
-            'commands.*.workflow_stream.items.*.item_type' => ['nullable', 'string', 'max:64'],
-            'commands.*.workflow_stream.items.*.content_type' => ['nullable', 'string', 'max:191'],
-            'commands.*.workflow_stream.max_pending_items' => ['nullable', 'integer', 'min:1'],
-            'commands.*.workflow_stream.error_reason' => ['nullable', 'string', 'max:191'],
-            'commands.*.workflow_stream.retention_seconds' => ['nullable', 'integer', 'min:1'],
-            'sticky_cache' => ['nullable', 'array'],
-            'sticky_cache.worker_id' => ['required_with:sticky_cache', 'string', 'max:255'],
-            'sticky_cache.workflow_id' => ['required_with:sticky_cache', 'string', 'max:255'],
-            'sticky_cache.run_id' => ['required_with:sticky_cache', 'string', 'max:255'],
-            'sticky_cache.build_id' => ['required_with:sticky_cache', 'string', 'max:255'],
-            'sticky_cache.ttl_seconds' => ['required_with:sticky_cache', 'integer', 'min:1', 'max:3600'],
-            'sticky_cache.metrics' => ['nullable', 'array'],
-            'sticky_cache.metrics.hit' => ['nullable', 'integer', 'min:0'],
-            'sticky_cache.metrics.miss' => ['nullable', 'integer', 'min:0'],
-            'sticky_cache.metrics.eviction' => ['nullable', 'integer', 'min:0'],
-            'sticky_cache.metrics.forced_cold_replay' => ['nullable', 'integer', 'min:0'],
-        ];
+        $completionRules = WorkflowTaskCompletionValidation::rules();
 
         $topLevelRules = [];
         if ($group) {
diff --git a/app/Support/WorkflowTaskCompletionValidation.php b/app/Support/WorkflowTaskCompletionValidation.php
new file mode 100644
index 000000000..591defb2c
--- /dev/null
+++ b/app/Support/WorkflowTaskCompletionValidation.php
@@ -0,0 +1,163 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Support;
+
+use Workflow\V2\Support\WorkflowCommandNormalizer;
+
+/** Transport rules retain the package command grammar before semantic normalization. */
+final class WorkflowTaskCompletionValidation
+{
+    private const REQUIRED_WORKFLOW_STREAM = 'required_with:commands.*.workflow_stream';
+
+    /** @return array<string, list<string>> */
+    public static function rules(): array
+    {
+        return [
+            'lease_owner' => ['required', 'string'],
+            'workflow_task_attempt' => ['required', 'integer', 'min:1'],
+            'commands' => ['required', 'array', 'min:1'],
+            'commands.*.type' => ['required', 'string'],
+            'commands.*.selection_group_id' => ['sometimes', 'string'],
+            'commands.*.member_key' => ['sometimes', 'string'],
+            'commands.*.member_index' => ['sometimes', 'integer', 'min:0'],
+            'commands.*.member_base_sequence' => ['sometimes', 'integer', 'min:1'],
+            'commands.*.member_size' => ['sometimes', 'integer', 'min:1'],
+            'commands.*.operation_kind' => ['sometimes', 'string'],
+            'commands.*.operation_identity' => ['sometimes', 'string'],
+            'commands.*.cancellation_scope_id' => ['sometimes', 'string', 'min:1', 'max:255'],
+            'commands.*.cancellation_cleanup' => ['sometimes', 'required', 'array:scope_id,request_id,delivery_history_event_id'],
+            'commands.*.cancellation_cleanup.scope_id' => ['sometimes', 'required', 'string', 'max:255'],
+            'commands.*.cancellation_cleanup.request_id' => ['required_with:commands.*.cancellation_cleanup', 'string', 'max:255'],
+            'commands.*.cancellation_cleanup.delivery_history_event_id' => ['required_with:commands.*.cancellation_cleanup', 'string', 'max:255'],
+            'commands.*.result' => ['nullable'],
+            'commands.*.activity_type' => ['nullable', 'string'],
+            'commands.*.arguments' => ['nullable'],
+            'commands.*.connection' => ['nullable', 'string'],
+            'commands.*.queue' => ['nullable', 'string'],
+            'commands.*.retry_policy' => ['nullable', 'array'],
+            'commands.*.retry_policy.max_attempts' => ['nullable', 'integer', 'min:1'],
+            'commands.*.retry_policy.backoff_seconds' => ['nullable', 'array'],
+            'commands.*.retry_policy.backoff_seconds.*' => ['integer', 'min:0'],
+            'commands.*.retry_policy.non_retryable_error_types' => ['nullable', 'array'],
+            'commands.*.retry_policy.non_retryable_error_types.*' => ['string'],
+            'commands.*.retry_policy.*' => ['nullable'],
+            'commands.*.start_to_close_timeout' => ['nullable', 'integer', 'min:1'],
+            'commands.*.schedule_to_start_timeout' => ['nullable', 'integer', 'min:1'],
+            'commands.*.schedule_to_close_timeout' => ['nullable', 'integer', 'min:1'],
+            'commands.*.heartbeat_timeout' => ['nullable', 'integer', 'min:1'],
+            'commands.*.execution_mode' => ['nullable', 'string', 'in:local'],
+            'commands.*.outcome' => ['nullable', 'string', 'in:completed,failed,timed_out,cancelled'],
+            'commands.*.attempts' => ['nullable', 'array', 'max:100'],
+            'commands.*.attempts.*.attempt_id' => ['nullable', 'string', 'max:255'],
+            'commands.*.attempts.*.attempt_number' => ['required', 'integer', 'min:1'],
+            'commands.*.attempts.*.outcome' => ['required', 'string', 'in:completed,failed,timed_out,cancelled'],
+            'commands.*.attempts.*.duration_ms' => ['nullable', 'integer', 'min:0'],
+            'commands.*.attempts.*.message' => ['nullable', 'string'],
+            'commands.*.attempts.*.exception_type' => ['nullable', 'string', 'max:255'],
+            'commands.*.attempts.*.non_retryable' => ['nullable', 'boolean'],
+            'commands.*.attempts.*.timeout_kind' => ['nullable', 'string', 'in:start_to_close,schedule_to_close,heartbeat'],
+            'commands.*.attempts.*.retry_reason' => ['nullable', 'string', 'in:failure,timeout,cold_replay'],
+            'commands.*.attempts.*.backoff_seconds' => ['nullable', 'integer', 'min:0'],
+            'commands.*.attempts.*.heartbeats' => ['nullable', 'array', 'max:1000'],
+            'commands.*.attempts.*.heartbeats.*.details' => ['nullable', 'array'],
+            'commands.*.attempts.*.heartbeats.*.elapsed_ms' => ['nullable', 'integer', 'min:0'],
+            'commands.*.attempts.*.heartbeats.*.*' => ['nullable'],
+            'commands.*.attempts.*.*' => ['nullable'],
+            'commands.*.worker_session' => ['nullable', 'array'],
+            'commands.*.worker_session.session_id' => ['nullable', 'string', 'max:255'],
+            'commands.*.worker_session.connection' => ['nullable', 'string', 'max:255'],
+            'commands.*.worker_session.queue' => ['nullable', 'string', 'max:255'],
+            'commands.*.worker_session.requirements' => ['nullable', 'array'],
+            'commands.*.worker_session.requirements.*' => ['string', 'max:255'],
+            'commands.*.worker_session.lease_seconds' => ['nullable', 'integer', 'min:1'],
+            'commands.*.worker_session.ttl_seconds' => ['nullable', 'integer', 'min:1'],
+            'commands.*.worker_session.max_concurrent_activities' => ['nullable', 'integer', 'min:1'],
+            'commands.*.worker_session.create_if_missing' => ['nullable', 'boolean'],
+            'commands.*.worker_session.allow_reacquire_after_failure' => ['nullable', 'boolean'],
+            'commands.*.execution_timeout_seconds' => ['nullable', 'integer', 'min:1'],
+            'commands.*.run_timeout_seconds' => ['nullable', 'integer', 'min:1'],
+            'commands.*.workflow_type' => ['nullable', 'string'],
+            'commands.*.delay_seconds' => ['nullable', 'integer', 'min:0'],
+            'commands.*.message' => ['nullable', 'string'],
+            'commands.*.timeout_kind' => ['nullable', 'string', 'in:start_to_close,schedule_to_close,heartbeat'],
+            'commands.*.payload_codec' => ['nullable', 'string'],
+            'commands.*.update_id' => ['nullable', 'string'],
+            'commands.*.exception_class' => ['nullable', 'string'],
+            'commands.*.exception_type' => ['nullable', 'string'],
+            'commands.*.exception' => ['nullable', 'array'],
+            'commands.*.failed_step_sequence' => ['nullable', 'integer', 'min:1'],
+            'commands.*.failed_activity_execution_id' => ['nullable', 'string', 'max:255'],
+            'commands.*.change_id' => ['nullable', 'string'],
+            'commands.*.version' => ['nullable', 'integer'],
+            'commands.*.min_supported' => ['nullable', 'integer'],
+            'commands.*.max_supported' => ['nullable', 'integer'],
+            'commands.*.attributes' => ['nullable', 'array'],
+            'commands.*.attribute_types' => ['nullable', 'array'],
+            'commands.*.attribute_types.*' => ['string'],
+            'commands.*.entries' => ['nullable', 'array'],
+            'commands.*.non_retryable' => ['nullable', 'boolean'],
+            'commands.*.parent_close_policy' => ['nullable', 'string'],
+            'commands.*.cancellation_policy' => ['nullable', 'string', 'in:try_cancel,wait_cancellation_completed,abandon'],
+            'commands.*.condition_key' => ['nullable', 'string'],
+            'commands.*.condition_definition_fingerprint' => ['nullable', 'string'],
+            'commands.*.condition_wait_occurrence_id' => ['nullable', 'string'],
+            'commands.*.signal_name' => ['nullable', 'string'],
+            'commands.*.timeout_seconds' => ['nullable', 'integer', 'min:0'],
+            'commands.*.endpoint_name' => ['nullable', 'string', 'max:191'],
+            'commands.*.service_name' => ['nullable', 'string', 'max:191'],
+            'commands.*.operation_name' => ['nullable', 'string', 'max:191'],
+            'commands.*.request_payload' => ['nullable'],
+            'commands.*.namespace' => ['nullable', 'string', 'max:191'],
+            'commands.*.caller_namespace' => ['nullable', 'string', 'max:191'],
+            'commands.*.service_call_id' => ['nullable', 'string', 'max:191'],
+            'commands.*.idempotency_key' => ['nullable', 'string', 'max:191'],
+            'commands.*.mode_override' => ['nullable', 'string', 'in:sync,async'],
+            'commands.*.wait_for' => ['nullable', 'string', 'in:accepted,completed'],
+            'commands.*.wait_timeout_seconds' => ['nullable', 'integer', 'min:0'],
+            'commands.*.target_workflow_instance_id' => ['nullable', 'string', 'max:191'],
+            'commands.*.target_workflow_run_id' => ['nullable', 'string', 'max:191'],
+            'commands.*.business_key' => ['nullable', 'string', 'max:191'],
+            'commands.*.labels' => ['nullable', 'array'],
+            'commands.*.memo' => ['nullable', 'array'],
+            'commands.*.search_attributes' => ['nullable', 'array'],
+            'commands.*.duplicate_start_policy' => ['nullable', 'string', 'in:reject_duplicate,return_existing_active'],
+            'commands.*.metadata' => ['nullable', 'array'],
+            'commands.*.request_payload_reference' => ['nullable', 'string', 'max:191'],
+            'commands.*.principal_subject' => ['prohibited'],
+            'commands.*.principal_method' => ['prohibited'],
+            'commands.*.principal_roles' => ['prohibited'],
+            'commands.*.principal_tenant' => ['prohibited'],
+            'commands.*.principal_claims' => ['prohibited'],
+            ...WorkflowCommandNormalizer::parallelMetadataValidationRules(),
+            'commands.*.workflow_stream' => ['nullable', 'array'],
+            'commands.*.workflow_stream.operation' => [self::REQUIRED_WORKFLOW_STREAM, 'string', 'in:append,close,error'],
+            'commands.*.workflow_stream.stream_name' => [self::REQUIRED_WORKFLOW_STREAM, 'string', 'max:191'],
+            'commands.*.workflow_stream.command_identity' => [self::REQUIRED_WORKFLOW_STREAM, 'string', 'max:191'],
+            'commands.*.workflow_stream.command_ordinal' => [self::REQUIRED_WORKFLOW_STREAM, 'integer', 'min:0'],
+            'commands.*.workflow_stream.items' => ['nullable', 'array', 'max:'.WorkflowStreamService::DEFAULT_MAX_ITEMS_PER_APPEND],
+            'commands.*.workflow_stream.items.*' => ['array'],
+            'commands.*.workflow_stream.items.*.payload' => ['nullable'],
+            'commands.*.workflow_stream.items.*.payload_reference' => ['nullable', 'string', 'max:191'],
+            'commands.*.workflow_stream.items.*.payload_codec' => ['nullable', 'string', 'max:64'],
+            'commands.*.workflow_stream.items.*.idempotency_key' => ['nullable', 'string', 'max:191'],
+            'commands.*.workflow_stream.items.*.item_type' => ['nullable', 'string', 'max:64'],
+            'commands.*.workflow_stream.items.*.content_type' => ['nullable', 'string', 'max:191'],
+            'commands.*.workflow_stream.max_pending_items' => ['nullable', 'integer', 'min:1'],
+            'commands.*.workflow_stream.error_reason' => ['nullable', 'string', 'max:191'],
+            'commands.*.workflow_stream.retention_seconds' => ['nullable', 'integer', 'min:1'],
+            'sticky_cache' => ['nullable', 'array'],
+            'sticky_cache.worker_id' => ['required_with:sticky_cache', 'string', 'max:255'],
+            'sticky_cache.workflow_id' => ['required_with:sticky_cache', 'string', 'max:255'],
+            'sticky_cache.run_id' => ['required_with:sticky_cache', 'string', 'max:255'],
+            'sticky_cache.build_id' => ['required_with:sticky_cache', 'string', 'max:255'],
+            'sticky_cache.ttl_seconds' => ['required_with:sticky_cache', 'integer', 'min:1', 'max:3600'],
+            'sticky_cache.metrics' => ['nullable', 'array'],
+            'sticky_cache.metrics.hit' => ['nullable', 'integer', 'min:0'],
+            'sticky_cache.metrics.miss' => ['nullable', 'integer', 'min:0'],
+            'sticky_cache.metrics.eviction' => ['nullable', 'integer', 'min:0'],
+            'sticky_cache.metrics.forced_cold_replay' => ['nullable', 'integer', 'min:0'],
+        ];
+    }
+}
diff --git a/composer.json b/composer.json
index e40bcd2d7..ec9ad5514 100644
--- a/composer.json
+++ b/composer.json
@@ -48,7 +48,7 @@
     },
     "extra": {
         "durable-workflow": {
-            "product-train": "2.10.0"
+            "product-train": "2.10.1"
         },
         "laravel": {
             "dont-discover": []
diff --git a/composer.lock b/composer.lock
index a76e2a3f7..8e9e72613 100644
--- a/composer.lock
+++ b/composer.lock
@@ -4,7 +4,7 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
         "This file is @generated automatically"
     ],
-    "content-hash": "6efd01e2e4b94293e21ace88e7088f04",
+    "content-hash": "050062197e287c4c7ddc1ccd2605d0e5",
     "packages": [
         {
             "name": "apache/avro",
diff --git a/docker-compose.dedicated-matching.yml b/docker-compose.dedicated-matching.yml
index 77b4b2b41..1ec3d1349 100644
--- a/docker-compose.dedicated-matching.yml
+++ b/docker-compose.dedicated-matching.yml
@@ -32,13 +32,13 @@ name: durable-workflow-server
 # daemon reports `shape: dedicated`.
 
 # Generated by scripts/ci/sync-source-release.mjs. Do not edit the fallback.
-x-server-image: &server-image ${DW_SERVER_IMAGE:-durableworkflow/server:${DW_SERVER_TAG:-2.10.0}}
+x-server-image: &server-image ${DW_SERVER_IMAGE:-durableworkflow/server:${DW_SERVER_TAG:-2.10.1}}
 
 x-server-environment: &server-environment
   APP_NAME: "Durable Workflow Server"
   APP_ENV: ${APP_ENV:-local}
   DW_SERVER_KEY: ${DW_SERVER_KEY:-}
-  APP_VERSION: ${APP_VERSION:-${DW_SERVER_TAG:-2.10.0}}
+  APP_VERSION: ${APP_VERSION:-${DW_SERVER_TAG:-2.10.1}}
   APP_DEBUG: ${APP_DEBUG:-false}
   DB_CONNECTION: mysql
   DB_HOST: mysql
diff --git a/docker-compose.memo-rolling.yml b/docker-compose.memo-rolling.yml
index 1e43c93b7..83147fc2b 100644
--- a/docker-compose.memo-rolling.yml
+++ b/docker-compose.memo-rolling.yml
@@ -49,14 +49,14 @@ services:
     command: ["server-bootstrap"]
     environment:
       <<: *runtime-environment
-      APP_VERSION: ${APP_VERSION:-2.10.0}
+      APP_VERSION: ${APP_VERSION:-2.10.1}
 
   successor:
     image: ${DW_MEMO_SUCCESSOR_IMAGE:-durable-workflow/server-memo-rolling:local}
     ports: !override []
     environment:
       <<: *runtime-environment
-      APP_VERSION: ${APP_VERSION:-2.10.0}
+      APP_VERSION: ${APP_VERSION:-2.10.1}
       DW_SERVER_ID: memo-successor
       DW_SERVER_TOPOLOGY_SHAPE: standalone_server
       DW_SERVER_PROCESS_CLASS: server_http_node
diff --git a/docker-compose.published.yml b/docker-compose.published.yml
index 7514a273a..cf3bed2b7 100644
--- a/docker-compose.published.yml
+++ b/docker-compose.published.yml
@@ -1,13 +1,13 @@
 name: durable-workflow-server
 
 # Generated by scripts/ci/sync-source-release.mjs. Do not edit the fallback.
-x-server-image: &server-image ${DW_SERVER_IMAGE:-durableworkflow/server:${DW_SERVER_TAG:-2.10.0}}
+x-server-image: &server-image ${DW_SERVER_IMAGE:-durableworkflow/server:${DW_SERVER_TAG:-2.10.1}}
 
 x-server-environment: &server-environment
   APP_NAME: "Durable Workflow Server"
   APP_ENV: ${APP_ENV:-local}
   DW_SERVER_KEY: ${DW_SERVER_KEY:-}
-  APP_VERSION: ${APP_VERSION:-${DW_SERVER_TAG:-2.10.0}}
+  APP_VERSION: ${APP_VERSION:-${DW_SERVER_TAG:-2.10.1}}
   APP_DEBUG: ${APP_DEBUG:-false}
   LOG_CHANNEL: ${LOG_CHANNEL:-stderr}
   LOG_LEVEL: ${LOG_LEVEL:-info}
diff --git a/docker-compose.small-cluster.yml b/docker-compose.small-cluster.yml
index 5750b765b..b416bcf96 100644
--- a/docker-compose.small-cluster.yml
+++ b/docker-compose.small-cluster.yml
@@ -12,7 +12,7 @@ x-server-build: &server-build
 x-server-environment: &server-environment
   APP_NAME: "Durable Workflow Server"
   APP_ENV: testing
-  APP_VERSION: ${APP_VERSION:-2.10.0}
+  APP_VERSION: ${APP_VERSION:-2.10.1}
   APP_DEBUG: "false"
   DW_SERVER_KEY: ${DW_SERVER_KEY:-base64:5Zt4nUhlCm3DD0nLXZJQdHiwPfb56yGo9gNV/g3jYbY=}
   DB_CONNECTION: ${DW_SMALL_CLUSTER_DB:-mysql}
diff --git a/docker-compose.yml b/docker-compose.yml
index ff6b2bb1e..c7d5d7b5a 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -15,7 +15,7 @@ services:
       DW_SERVER_KEY: "${DW_SERVER_KEY:-}"
       DW_SERVER_TOPOLOGY_SHAPE: standalone_server
       DW_SERVER_PROCESS_CLASS: server_http_node
-      APP_VERSION: "${APP_VERSION:-2.10.0}"
+      APP_VERSION: "${APP_VERSION:-2.10.1}"
       APP_DEBUG: "false"
       DB_CONNECTION: mysql
       DB_HOST: mysql
@@ -62,7 +62,7 @@ services:
       APP_NAME: "Durable Workflow Server"
       APP_ENV: local
       DW_SERVER_KEY: "${DW_SERVER_KEY:-}"
-      APP_VERSION: "${APP_VERSION:-2.10.0}"
+      APP_VERSION: "${APP_VERSION:-2.10.1}"
       APP_DEBUG: "false"
       DB_CONNECTION: mysql
       DB_HOST: mysql
@@ -124,7 +124,7 @@ services:
       DW_SERVER_KEY: "${DW_SERVER_KEY:-}"
       DW_SERVER_TOPOLOGY_SHAPE: standalone_server
       DW_SERVER_PROCESS_CLASS: worker_node
-      APP_VERSION: "${APP_VERSION:-2.10.0}"
+      APP_VERSION: "${APP_VERSION:-2.10.1}"
       DB_CONNECTION: mysql
       DB_HOST: mysql
       DB_PORT: 3306
@@ -178,7 +178,7 @@ services:
       DW_SERVER_KEY: "${DW_SERVER_KEY:-}"
       DW_SERVER_TOPOLOGY_SHAPE: standalone_server
       DW_SERVER_PROCESS_CLASS: scheduler_node
-      APP_VERSION: "${APP_VERSION:-2.10.0}"
+      APP_VERSION: "${APP_VERSION:-2.10.1}"
       DB_CONNECTION: mysql
       DB_HOST: mysql
       DB_PORT: 3306
diff --git a/docs/select-member-cancellation-recovery.md b/docs/select-member-cancellation-recovery.md
new file mode 100644
index 000000000..1f8393344
--- /dev/null
+++ b/docs/select-member-cancellation-recovery.md
@@ -0,0 +1,37 @@
+# Recover a workflow blocked while cancelling a select member
+
+PHP Server 2.10.0 discards select-member cancellation identity fields
+when validating a workflow-task completion. The runtime then refuses the
+`cancel_selection_operation` command. A worker can report that refusal as a
+workflow replay error, leaving the run waiting with `workflow_replay_blocked`.
+The activity the workflow tried to cancel can still be queued or running.
+
+Upgrade to PHP Server 2.10.1 or later before repairing affected runs.
+The correction preserves the existing command format and does not require an
+SDK or Workflow dependency upgrade. It does not automatically retry blocked
+runs or undo an activity that has already executed.
+
+## Inspect and repair the original run
+
+Check the selected run's history and activity state. Confirm that the failure
+names selection cancellation validation rather than another replay error.
+Keep the original workflow and run IDs. Use the existing selected-run repair
+endpoint with an operator-authorized token and the original namespace:
+
+```sh
+curl --fail-with-body --request POST \
+  "$DW_SERVER_URL/api/workflows/$WORKFLOW_ID/runs/$RUN_ID/repair" \
+  --header "Authorization: Bearer $DW_API_TOKEN" \
+  --header "X-Namespace: $DW_NAMESPACE" \
+  --header 'X-Durable-Workflow-Control-Plane-Version: 2' \
+  --header 'Content-Type: application/json' \
+  --data '{"request_id":"repair-select-member-cancellation"}'
+```
+
+Use URL-encoded identifiers in the path. Keep a compatible workflow worker
+running on the original queue. Repair makes the original run available for
+replay; the workflow can then submit its original cancellation and complete.
+Verify the new workflow-task outcome and the member's recorded outcome in
+history. A still-queued losing activity records `SelectionOperationCancelled`
+and cannot be claimed after cancellation. Already completed operations retain
+their recorded results.
diff --git a/k8s/README.md b/k8s/README.md
index b58d07ed8..1f64202c7 100644
--- a/k8s/README.md
+++ b/k8s/README.md
@@ -13,7 +13,7 @@ The checked-in manifests are synchronized with the repository's stable source
 release and pin its Docker Hub tag:
 
 ```text
-durableworkflow/server:2.10.0
+durableworkflow/server:2.10.1
 ```
 
 Before production use, patch every workload image to the exact published tag or
@@ -21,15 +21,15 @@ digest you intend to run:
 
 ```bash
 kubectl set image -n durable-workflow deploy/durable-workflow-server \
-  server=durableworkflow/server:2.10.0
+  server=durableworkflow/server:2.10.1
 kubectl set image -n durable-workflow deploy/durable-workflow-worker \
-  worker=durableworkflow/server:2.10.0
+  worker=durableworkflow/server:2.10.1
 kubectl set image -n durable-workflow cronjob/durable-workflow-scheduler \
-  scheduler=durableworkflow/server:2.10.0
+  scheduler=durableworkflow/server:2.10.1
 ```
 
 GitHub Container Registry publishes the same release line at
-`ghcr.io/durable-workflow/server:2.10.0`. Digest pinning is preferred for strict
+`ghcr.io/durable-workflow/server:2.10.1`. Digest pinning is preferred for strict
 change control.
 
 The manifests expect you to provide:
diff --git a/k8s/helm/durable-workflow/Chart.yaml b/k8s/helm/durable-workflow/Chart.yaml
index 9f0ea4438..ee733b24b 100644
--- a/k8s/helm/durable-workflow/Chart.yaml
+++ b/k8s/helm/durable-workflow/Chart.yaml
@@ -5,11 +5,11 @@ type: application
 # The chart's own semver version. Bumped on every chart release; treated as
 # independent of the server image version (appVersion). Breaking-change rules
 # for this version live in docs/UPGRADING.md alongside the chart.
-version: 0.2.2
+version: 0.2.3
 # The immutable Durable Workflow Server identity this chart release packages.
 # The onboarding default in values.yaml and appVersion are generated from the
 # checked-in source release record.
-appVersion: "2.10.0"
+appVersion: "2.10.1"
 kubeVersion: ">=1.27.0-0"
 home: https://durable-workflow.github.io/docs/2.0/deployment
 sources:
@@ -30,7 +30,7 @@ annotations:
   # exact commit that most recently changed the packaged chart.
   org.opencontainers.image.source: https://github.com/durable-workflow/server
   dev.durable-workflow.source-revision: "unreleased"
-  dev.durable-workflow.image-reference: "docker.io/durableworkflow/server:2.10.0"
+  dev.durable-workflow.image-reference: "docker.io/durableworkflow/server:2.10.1"
   artifacthub.io/license: MIT
   artifacthub.io/category: integration-delivery
   # Free-form changelog for the current chart release shown by Artifact Hub.
diff --git a/k8s/helm/durable-workflow/README.md b/k8s/helm/durable-workflow/README.md
index 61b0d7a20..4883a86fa 100644
--- a/k8s/helm/durable-workflow/README.md
+++ b/k8s/helm/durable-workflow/README.md
@@ -63,7 +63,7 @@ helm install durable-workflow ./k8s/helm/durable-workflow \
 
 ```yaml
 image:
-  tag: "2.10.0"
+  tag: "2.10.1"
   # Pin a digest in production:
   # digest: "sha256:abc123..."
   # memoPayloadStorage: "raw-json-v1" # Required for a digest or custom image.
diff --git a/k8s/helm/durable-workflow/ci/existing-secrets-values.yaml b/k8s/helm/durable-workflow/ci/existing-secrets-values.yaml
index 9072e9a18..3d1e2d812 100644
--- a/k8s/helm/durable-workflow/ci/existing-secrets-values.yaml
+++ b/k8s/helm/durable-workflow/ci/existing-secrets-values.yaml
@@ -1,7 +1,7 @@
 # CI fixture: GitOps / externally-managed-secret path. The chart consumes
 # existing Secrets and renders no Secret resources of its own.
 image:
-  tag: "2.10.0"
+  tag: "2.10.1"
 
 externalDatabase:
   connection: pgsql
diff --git a/k8s/helm/durable-workflow/ci/ingress-and-hpa-values.yaml b/k8s/helm/durable-workflow/ci/ingress-and-hpa-values.yaml
index b1d930ed5..ab05a5d9f 100644
--- a/k8s/helm/durable-workflow/ci/ingress-and-hpa-values.yaml
+++ b/k8s/helm/durable-workflow/ci/ingress-and-hpa-values.yaml
@@ -1,6 +1,6 @@
 # CI fixture: ingress + autoscaling enabled. Exercises optional templates.
 image:
-  tag: "2.10.0"
+  tag: "2.10.1"
 
 externalDatabase:
   connection: mysql
diff --git a/k8s/helm/durable-workflow/ci/inline-secrets-values.yaml b/k8s/helm/durable-workflow/ci/inline-secrets-values.yaml
index 9031db341..5a32320fd 100644
--- a/k8s/helm/durable-workflow/ci/inline-secrets-values.yaml
+++ b/k8s/helm/durable-workflow/ci/inline-secrets-values.yaml
@@ -2,7 +2,7 @@
 # chart's render path is exercised end-to-end. Real deployments should use
 # existingSecret instead.
 image:
-  tag: "2.10.0"
+  tag: "2.10.1"
 
 externalDatabase:
   connection: mysql
diff --git a/k8s/helm/durable-workflow/templates/_helpers.tpl b/k8s/helm/durable-workflow/templates/_helpers.tpl
index e0177287c..df6f4a5b7 100644
--- a/k8s/helm/durable-workflow/templates/_helpers.tpl
+++ b/k8s/helm/durable-workflow/templates/_helpers.tpl
@@ -88,7 +88,7 @@ resolved by an explicit capability declaration or an existing workload marker.
 {{- define "durable-workflow.memoPayloadStorageForImage" -}}
 {{- $image := toString . -}}
 {{- $normalized := regexReplaceAll "^index\\.docker\\.io/" $image "docker.io/" -}}
-{{- if eq $normalized "docker.io/durableworkflow/server:2.10.0" -}}
+{{- if eq $normalized "docker.io/durableworkflow/server:2.10.1" -}}
 dual-v1
 {{- else if regexMatch "^docker\\.io/durableworkflow/server:2\\.0\\.0-rc\\.[0-9]+$" $normalized -}}
 {{- $releaseCandidate := atoi (regexFind "[0-9]+$" $normalized) -}}
diff --git a/k8s/helm/durable-workflow/values.yaml b/k8s/helm/durable-workflow/values.yaml
index b0f960047..d521dd292 100644
--- a/k8s/helm/durable-workflow/values.yaml
+++ b/k8s/helm/durable-workflow/values.yaml
@@ -21,7 +21,7 @@ image:
   registry: docker.io
   repository: durableworkflow/server
   # Generated by scripts/ci/sync-source-release.mjs. Do not edit this default.
-  tag: "2.10.0"
+  tag: "2.10.1"
   # Optional digest pin. When set, takes precedence over tag for change control.
   # Example: "sha256:abc123..."
   digest: ""
diff --git a/k8s/helm/examples/values-dev.yaml b/k8s/helm/examples/values-dev.yaml
index 68ccfe92e..9ba84bb69 100644
--- a/k8s/helm/examples/values-dev.yaml
+++ b/k8s/helm/examples/values-dev.yaml
@@ -3,7 +3,7 @@
 # shape in production.
 
 image:
-  tag: "2.10.0"
+  tag: "2.10.1"
 
 externalDatabase:
   connection: mysql
diff --git a/k8s/helm/examples/values-external-secrets-operator.yaml b/k8s/helm/examples/values-external-secrets-operator.yaml
index 83b970697..bc6d93e1b 100644
--- a/k8s/helm/examples/values-external-secrets-operator.yaml
+++ b/k8s/helm/examples/values-external-secrets-operator.yaml
@@ -5,7 +5,7 @@
 # concern.
 
 image:
-  tag: "2.10.0"
+  tag: "2.10.1"
 
 externalDatabase:
   connection: pgsql
diff --git a/k8s/helm/examples/values-production-existing-secrets.yaml b/k8s/helm/examples/values-production-existing-secrets.yaml
index b427f40d5..1bcccace7 100644
--- a/k8s/helm/examples/values-production-existing-secrets.yaml
+++ b/k8s/helm/examples/values-production-existing-secrets.yaml
@@ -10,7 +10,7 @@ image:
   repository: durable-workflow/server
   # Pin a digest in production for change-control auditability.
   digest: ""    # e.g. "sha256:abc123..."
-  tag: "2.10.0"
+  tag: "2.10.1"
 
 externalDatabase:
   connection: pgsql
diff --git a/k8s/migration-job.yaml b/k8s/migration-job.yaml
index 8eb2da137..f1d87ebdf 100644
--- a/k8s/migration-job.yaml
+++ b/k8s/migration-job.yaml
@@ -13,7 +13,7 @@ spec:
       restartPolicy: OnFailure
       containers:
         - name: migrate
-          image: durableworkflow/server:2.10.0
+          image: durableworkflow/server:2.10.1
           command: ["server-entrypoint"]
           args: ["server-bootstrap"]
           envFrom:
diff --git a/k8s/scheduler-cronjob.yaml b/k8s/scheduler-cronjob.yaml
index f80da825c..fed3121ca 100644
--- a/k8s/scheduler-cronjob.yaml
+++ b/k8s/scheduler-cronjob.yaml
@@ -24,7 +24,7 @@ spec:
           restartPolicy: Never
           containers:
             - name: scheduler
-              image: durableworkflow/server:2.10.0
+              image: durableworkflow/server:2.10.1
               command: ["server-entrypoint"]
               args:
                 - sh
diff --git a/k8s/secret.yaml b/k8s/secret.yaml
index 5084f55ac..5236c860a 100644
--- a/k8s/secret.yaml
+++ b/k8s/secret.yaml
@@ -12,7 +12,7 @@ metadata:
     app.kubernetes.io/name: durable-workflow
 data:
   APP_NAME: "Durable Workflow Server"
-  APP_VERSION: "2.10.0"
+  APP_VERSION: "2.10.1"
   APP_ENV: production
   APP_DEBUG: "false"
   DB_CONNECTION: mysql
diff --git a/k8s/server-deployment.yaml b/k8s/server-deployment.yaml
index 214da09e1..38ca279b0 100644
--- a/k8s/server-deployment.yaml
+++ b/k8s/server-deployment.yaml
@@ -23,7 +23,7 @@ spec:
     spec:
       containers:
         - name: server
-          image: durableworkflow/server:2.10.0
+          image: durableworkflow/server:2.10.1
           ports:
             - containerPort: 8080
               name: http
diff --git a/k8s/worker-deployment.yaml b/k8s/worker-deployment.yaml
index 84a6df475..39e90f133 100644
--- a/k8s/worker-deployment.yaml
+++ b/k8s/worker-deployment.yaml
@@ -19,7 +19,7 @@ spec:
     spec:
       containers:
         - name: worker
-          image: durableworkflow/server:2.10.0
+          image: durableworkflow/server:2.10.1
           command: ["server-entrypoint"]
           args: ["php", "artisan", "queue:work", "--sleep=1", "--tries=3", "--max-time=3600"]
           envFrom:
diff --git a/resources/release/source-release.json b/resources/release/source-release.json
index 271e80038..6d20c9916 100644
--- a/resources/release/source-release.json
+++ b/resources/release/source-release.json
@@ -1,9 +1,9 @@
 {
   "schema": "durable-workflow.server.source-release/v1",
   "server": {
-    "version": "2.10.0"
+    "version": "2.10.1"
   },
   "helm_chart": {
-    "version": "0.2.2"
+    "version": "0.2.3"
   }
 }
diff --git a/scripts/k8s-kind-smoke.sh b/scripts/k8s-kind-smoke.sh
index 3d5efad4e..5e4e2ab07 100755
--- a/scripts/k8s-kind-smoke.sh
+++ b/scripts/k8s-kind-smoke.sh
@@ -7,7 +7,7 @@ cluster="${K8S_SMOKE_CLUSTER:-durable-workflow-server-smoke}"
 image="${K8S_SMOKE_IMAGE:-durableworkflow/server:k8s-smoke}"
 # Generated by scripts/ci/sync-source-release.mjs so the smoke replaces the
 # same default shipped by the public manifests.
-manifest_image="durableworkflow/server:2.10.0"
+manifest_image="durableworkflow/server:2.10.1"
 kind_node_image="${K8S_SMOKE_KIND_NODE_IMAGE:-kindest/node:v1.29.4}"
 artifact_dir="${K8S_SMOKE_ARTIFACT_DIR:-/tmp/durable-workflow-k8s-kind-smoke-artifacts}"
 rendered_dir="${artifact_dir}/rendered-manifests"
diff --git a/tests/Feature/SelectionCancellationHttpTest.php b/tests/Feature/SelectionCancellationHttpTest.php
new file mode 100644
index 000000000..f9f10e199
--- /dev/null
+++ b/tests/Feature/SelectionCancellationHttpTest.php
@@ -0,0 +1,177 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Feature;
+
+use Illuminate\Foundation\Testing\RefreshDatabase;
+use Illuminate\Support\Facades\Queue;
+use Illuminate\Testing\TestResponse;
+use PHPUnit\Framework\Attributes\DataProvider;
+use Tests\Feature\Concerns\ServerTestHelpers;
+use Tests\TestCase;
+use Workflow\Serializers\Serializer;
+use Workflow\V2\Enums\HistoryEventType;
+use Workflow\V2\Enums\RunStatus;
+use Workflow\V2\Enums\TaskStatus;
+use Workflow\V2\Enums\TaskType;
+use Workflow\V2\Jobs\RunTimerTask;
+use Workflow\V2\Models\ActivityExecution;
+use Workflow\V2\Models\WorkflowHistoryEvent;
+use Workflow\V2\Models\WorkflowRun;
+use Workflow\V2\Models\WorkflowTask;
+
+final class SelectionCancellationHttpTest extends TestCase
+{
+    use RefreshDatabase;
+    use ServerTestHelpers;
+
+    protected function setUp(): void
+    {
+        parent::setUp();
+        Queue::fake();
+        $this->createNamespace('default');
+        $this->createNamespace('other');
+        $this->registerWorker('select-worker', 'select-http', supportedWorkflowTypes: ['select-http']);
+        $this->registerWorker('activity-worker', 'later', supportedActivityTypes: ['lose']);
+    }
+
+    public function test_losing_queued_activity_is_cancelled_through_http_and_cannot_be_claimed(): void
+    {
+        [$runId, $task, $cancel] = $this->stageTimerWinner();
+        $this->complete($task, [$cancel, [
+            'type' => 'complete_workflow', 'result' => Serializer::serialize(['timer-won', 9007199254740993, null, 'λ']),
+        ]])->assertOk()->assertJsonPath('recorded', true);
+
+        $this->assertSame('cancelled', ActivityExecution::query()->sole()->status->value);
+        $this->assertSame(1, WorkflowHistoryEvent::query()->where('workflow_run_id', $runId)
+            ->where('event_type', HistoryEventType::SelectionOperationCancelled->value)->count());
+        $this->postJson('/api/worker/activity-tasks/poll', [
+            'worker_id' => 'activity-worker', 'task_queue' => 'later',
+        ], $this->workerHeaders())->assertOk()->assertJsonPath('task', null);
+
+        $this->assertSame(RunStatus::Completed, WorkflowRun::query()->findOrFail($runId)->status);
+        $this->assertSame(0, WorkflowTask::query()->where('workflow_run_id', $runId)
+            ->where('task_type', TaskType::Activity->value)->where('status', TaskStatus::Leased->value)->count());
+    }
+
+    #[DataProvider('invalidMembers')]
+    public function test_invalid_or_foreign_member_cannot_cancel_the_original_activity(array $changes, string $namespace, int $status): void
+    {
+        [$runId, $task, $cancel] = $this->stageTimerWinner();
+        $before = WorkflowHistoryEvent::query()->where('workflow_run_id', $runId)->count();
+        $this->complete($task, [array_replace($cancel, $changes)], $namespace)->assertStatus($status);
+        $this->assertSame('pending', ActivityExecution::query()->sole()->status->value);
+        $this->assertSame($before, WorkflowHistoryEvent::query()->where('workflow_run_id', $runId)->count());
+        $this->assertSame(TaskStatus::Leased, WorkflowTask::query()->findOrFail($task['task_id'])->status);
+    }
+
+    public static function invalidMembers(): array
+    {
+        return [
+            'wrong operation' => [['operation_identity' => 'foreign-activity'], 'default', 409],
+            'wrong member' => [['member_key' => 'deadline'], 'default', 409],
+            'outside group' => [['member_base_sequence' => 3], 'default', 422],
+            'wrong namespace' => [[], 'other', 404],
+        ];
+    }
+
+    public function test_previously_blocked_run_can_be_repaired_and_cancel_its_original_member(): void
+    {
+        [$runId, $task, $cancel] = $this->stageTimerWinner();
+        $this->postJson('/api/worker/workflow-tasks/'.$task['task_id'].'/fail', [
+            'lease_owner' => 'select-worker', 'workflow_task_attempt' => $task['workflow_task_attempt'],
+            'failure' => [
+                'type' => 'ServerError',
+                'message' => 'Workflow task completion failed after commands were produced: Selection cancellation must identify one authored member within a durable selection group.',
+            ],
+        ], $this->workerHeaders())->assertOk()->assertJsonPath('recorded', true);
+        $this->assertSame(0, WorkflowTask::query()->where('workflow_run_id', $runId)
+            ->where('task_type', TaskType::Workflow->value)->where('status', TaskStatus::Ready->value)->count());
+
+        $this->postJson('/api/workflows/select-http/runs/'.$runId.'/repair', [
+            'request_id' => 'repair-select-validation',
+        ], $this->apiHeaders())->assertOk();
+        $this->complete($this->pollWorkflow(), [$cancel, [
+            'type' => 'complete_workflow', 'result' => Serializer::serialize('recovered'),
+        ]])->assertOk()->assertJsonPath('recorded', true);
+        $this->assertSame(RunStatus::Completed, WorkflowRun::query()->findOrFail($runId)->status);
+        $this->assertSame('cancelled', ActivityExecution::query()->sole()->status->value);
+    }
+
+    public function test_expired_original_claim_cannot_cancel_a_member(): void
+    {
+        [$runId, $task, $cancel] = $this->stageTimerWinner();
+        WorkflowTask::query()->findOrFail($task['task_id'])->forceFill(['lease_expires_at' => now()->subSecond()])->save();
+        $this->complete($task, [$cancel])->assertStatus(409)->assertJsonPath('reason', 'lease_expired');
+        $this->assertSame('pending', ActivityExecution::query()->sole()->status->value);
+        $this->assertSame(0, WorkflowHistoryEvent::query()->where('workflow_run_id', $runId)
+            ->where('event_type', HistoryEventType::SelectionOperationCancelled->value)->count());
+    }
+
+    #[DataProvider('requiredMemberFields')]
+    public function test_missing_identity_field_is_refused_without_mutation(string $field): void
+    {
+        [$runId, $task, $cancel] = $this->stageTimerWinner();
+        $before = WorkflowHistoryEvent::query()->where('workflow_run_id', $runId)->count();
+        unset($cancel[$field]);
+        $this->complete($task, [$cancel])->assertUnprocessable();
+        $this->assertSame('pending', ActivityExecution::query()->sole()->status->value);
+        $this->assertSame($before, WorkflowHistoryEvent::query()->where('workflow_run_id', $runId)->count());
+    }
+
+    public static function requiredMemberFields(): array
+    {
+        return array_map(static fn (string $field): array => [$field], [
+            'selection_group_id', 'member_key', 'member_index', 'member_base_sequence',
+            'member_size', 'operation_kind', 'operation_identity',
+        ]);
+    }
+
+    private function stageTimerWinner(): array
+    {
+        $start = $this->postJson('/api/workflows', [
+            'workflow_id' => 'select-http', 'workflow_type' => 'select-http', 'task_queue' => 'select-http',
+        ], $this->apiHeaders())->assertCreated();
+        $task = $this->pollWorkflow();
+        $commands = [];
+        foreach ([['schedule_activity', 'act', 'activity'], ['start_timer', 'deadline', 'timer']] as $index => [$type, $key, $kind]) {
+            $entry = [
+                'parallel_group_id' => 'select-calls:1:2', 'parallel_group_kind' => 'mixed',
+                'parallel_group_mode' => 'select', 'parallel_group_base_sequence' => 1,
+                'parallel_group_size' => 2, 'parallel_group_index' => $index,
+                'selection_member_key' => $key, 'selection_member_index' => $index,
+                'selection_member_base_sequence' => 1 + $index, 'selection_member_size' => 1,
+                'selection_member_kind' => $kind,
+            ];
+            $commands[] = array_merge([
+                'type' => $type, ...$entry, 'parallel_group_path' => [$entry],
+            ], $index === 0 ? ['activity_type' => 'lose', 'queue' => 'later'] : ['delay_seconds' => 0]);
+        }
+        $this->complete($task, $commands)->assertOk()->assertJsonPath('recorded', true);
+        $timerTask = WorkflowTask::query()->where('task_type', TaskType::Timer->value)->sole();
+        $this->app->call([new RunTimerTask($timerTask->id), 'handle']);
+        $cancel = [
+            'type' => 'cancel_selection_operation', 'selection_group_id' => 'select-calls:1:2',
+            'member_key' => 'act', 'member_index' => 0, 'member_base_sequence' => 1, 'member_size' => 1,
+            'operation_kind' => 'activity', 'operation_identity' => ActivityExecution::query()->sole()->id,
+        ];
+
+        return [$start->json('run_id'), $this->pollWorkflow(), $cancel];
+    }
+
+    private function pollWorkflow(): array
+    {
+        return $this->postJson('/api/worker/workflow-tasks/poll', [
+            'worker_id' => 'select-worker', 'task_queue' => 'select-http',
+        ], $this->workerHeaders())->assertOk()->json('task');
+    }
+
+    private function complete(array $task, array $commands, string $namespace = 'default'): TestResponse
+    {
+        return $this->postJson('/api/worker/workflow-tasks/'.$task['task_id'].'/complete', [
+            'lease_owner' => 'select-worker', 'workflow_task_attempt' => $task['workflow_task_attempt'],
+            'commands' => $commands,
+        ], $this->workerHeaders($namespace));
+    }
+}
diff --git a/tests/Feature/WorkflowTaskCommandFieldRetentionTest.php b/tests/Feature/WorkflowTaskCommandFieldRetentionTest.php
new file mode 100644
index 000000000..fd683ff28
--- /dev/null
+++ b/tests/Feature/WorkflowTaskCommandFieldRetentionTest.php
@@ -0,0 +1,100 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Feature;
+
+use App\Support\WorkflowTaskCompletionValidation;
+use Illuminate\Support\Facades\Validator;
+use Tests\TestCase;
+use Workflow\Serializers\Serializer;
+use Workflow\V2\Support\MemoPayload;
+use Workflow\V2\Support\WorkerProtocolVersion;
+use Workflow\V2\Support\WorkflowCommandNormalizer;
+
+final class WorkflowTaskCommandFieldRetentionTest extends TestCase
+{
+    public function test_http_validation_preserves_the_package_grammar_for_every_command_type(): void
+    {
+        $commands = $this->commands();
+        $types = array_merge(WorkerProtocolVersion::terminalCommandTypes(), WorkerProtocolVersion::nonTerminalCommandTypes());
+        $covered = array_column($commands, 'type');
+        sort($types);
+        sort($covered);
+        $this->assertSame($types, $covered, 'Every package command needs a field-retention example.');
+
+        foreach ($commands as $command) {
+            $normalized = WorkflowCommandNormalizer::normalize([$command]);
+            $validated = Validator::make([
+                'lease_owner' => 'original-worker', 'workflow_task_attempt' => 1,
+                'commands' => [$command],
+            ], WorkflowTaskCompletionValidation::rules())->validate();
+            $this->assertSame($normalized, WorkflowCommandNormalizer::normalize($validated['commands']), $command['type']);
+        }
+    }
+
+    public function test_unknown_fields_stay_out_and_server_principal_fields_are_prohibited(): void
+    {
+        $input = [
+            'lease_owner' => 'original-worker', 'workflow_task_attempt' => 1,
+            'commands' => [['type' => 'complete_workflow', 'result' => null, 'unknown' => 'discard']],
+        ];
+        $validated = Validator::make($input, WorkflowTaskCompletionValidation::rules())->validate();
+        $this->assertArrayNotHasKey('unknown', $validated['commands'][0]);
+        foreach (['principal_subject', 'principal_method', 'principal_roles', 'principal_tenant', 'principal_claims'] as $field) {
+            $forged = $input;
+            $forged['commands'][0][$field] = 'forged';
+            $this->assertTrue(Validator::make($forged, WorkflowTaskCompletionValidation::rules())->fails(), $field);
+        }
+    }
+
+    private function commands(): array
+    {
+        $payload = Serializer::serialize([9007199254740993, null, 'λ']);
+        $retry = ['max_attempts' => 2, 'backoff_seconds' => [1], 'non_retryable_error_types' => ['InvalidInput']];
+
+        return [
+            ['type' => 'complete_workflow', 'result' => $payload],
+            ['type' => 'fail_workflow', 'message' => 'original failure', 'exception_class' => 'OriginalFailure',
+                'non_retryable' => true, 'failed_step_sequence' => 1, 'failed_activity_execution_id' => 'original-activity',
+                'exception' => ['type' => 'OriginalFailure', 'message' => 'original failure']],
+            ['type' => 'continue_as_new', 'workflow_type' => 'next-type', 'queue' => 'next-queue', 'arguments' => $payload],
+            ['type' => 'cancel_selection_operation', 'selection_group_id' => 'select-calls:1:2',
+                'member_key' => '0', 'member_index' => 0, 'member_base_sequence' => 1, 'member_size' => 1,
+                'operation_kind' => 'activity', 'operation_identity' => 'original-activity'],
+            ['type' => 'schedule_activity', 'activity_type' => 'activity', 'arguments' => $payload,
+                'connection' => 'database', 'queue' => 'activities', 'retry_policy' => $retry,
+                'start_to_close_timeout' => 10, 'schedule_to_start_timeout' => 5,
+                'schedule_to_close_timeout' => 30, 'heartbeat_timeout' => 2],
+            ['type' => 'start_timer', 'delay_seconds' => 0],
+            ['type' => 'start_child_workflow', 'workflow_type' => 'child', 'arguments' => $payload,
+                'connection' => 'database', 'queue' => 'children', 'parent_close_policy' => 'abandon',
+                'cancellation_policy' => 'abandon', 'execution_timeout_seconds' => 30,
+                'run_timeout_seconds' => 10, 'retry_policy' => $retry],
+            ['type' => 'start_service_operation', 'endpoint_name' => 'endpoint', 'service_name' => 'service',
+                'operation_name' => 'operation', 'request_payload' => $payload, 'namespace' => 'target',
+                'caller_namespace' => 'source', 'service_call_id' => 'call-id', 'idempotency_key' => 'key',
+                'mode_override' => 'async', 'wait_for' => 'completed', 'wait_timeout_seconds' => 0,
+                'target_workflow_instance_id' => 'target-workflow', 'target_workflow_run_id' => 'target-run',
+                'connection' => 'database', 'queue' => 'target-queue', 'business_key' => 'business-key',
+                'labels' => ['label'], 'memo' => ['key' => 'value'], 'search_attributes' => ['State' => 'active'],
+                'duplicate_start_policy' => 'return_existing_active', 'metadata' => ['key' => 'value'],
+                'request_payload_reference' => 'reference-id'],
+            ['type' => 'complete_update', 'update_id' => 'update-id', 'result' => $payload],
+            ['type' => 'fail_update', 'update_id' => 'update-id', 'message' => 'failure',
+                'exception_type' => 'UpdateFailure', 'non_retryable' => true],
+            ['type' => 'record_side_effect', 'result' => $payload],
+            ['type' => 'record_local_activity', 'activity_type' => 'local', 'outcome' => 'completed',
+                'arguments' => $payload, 'result' => $payload, 'retry_policy' => $retry,
+                'start_to_close_timeout' => 10, 'schedule_to_close_timeout' => 30, 'heartbeat_timeout' => 2,
+                'attempts' => [['attempt_id' => 'local-attempt', 'attempt_number' => 1, 'outcome' => 'completed',
+                    'duration_ms' => 3, 'heartbeats' => [['elapsed_ms' => 1, 'details' => ['step' => 'started']]]]]],
+            ['type' => 'record_version_marker', 'change_id' => 'change', 'version' => 0, 'min_supported' => -1, 'max_supported' => 1],
+            ['type' => 'upsert_memo', 'entries' => MemoPayload::mapEnvelope(['key' => 'λ', 'delete' => null])],
+            ['type' => 'upsert_search_attributes', 'attributes' => ['State' => 'active'], 'attribute_types' => ['State' => 'keyword']],
+            ['type' => 'open_condition_wait', 'condition_key' => 'condition', 'timeout_seconds' => 0,
+                'condition_definition_fingerprint' => 'fingerprint', 'condition_wait_occurrence_id' => 'occurrence'],
+            ['type' => 'open_signal_wait', 'signal_name' => 'signal', 'timeout_seconds' => 0],
+        ];
+    }
+}