diff --git a/composer.json b/composer.json
index 8556574f..4db301fb 100644
--- a/composer.json
+++ b/composer.json
@@ -93,7 +93,7 @@
             }
         },
         "durable-workflow": {
-            "product-train": "3.6.0",
+            "product-train": "3.6.1",
             "supported-server-versions": "2.5.0",
             "worker-protocol-version": "1.20",
             "control-plane-version": "2",
diff --git a/docs/quickstart-contract.json b/docs/quickstart-contract.json
index 0db217f2..5709b6b5 100644
--- a/docs/quickstart-contract.json
+++ b/docs/quickstart-contract.json
@@ -3,8 +3,8 @@
   "schema_version": 2,
   "package": {
     "name": "durable-workflow/sdk",
-    "published_version": "3.6.0",
-    "composer_requirement": "3.6.0",
+    "published_version": "3.6.1",
+    "composer_requirement": "3.6.1",
     "onboarding_requirement": "^3.6"
   },
   "runtime_targets": {
diff --git a/src/Worker/ActivityContext.php b/src/Worker/ActivityContext.php
index 7bb2aeed..ca0471b8 100644
--- a/src/Worker/ActivityContext.php
+++ b/src/Worker/ActivityContext.php
@@ -12,9 +12,9 @@
 final class ActivityContext
 {
     public readonly ActivityRetryInfo $retryInfo;
-    /** Owning workflow_instance_id from the claim, or known parent local task. */
+    /** Original workflow_id from the public claim, or known parent local task. */
     public readonly ?string $workflowId;
-    /** Original owning workflow_run_id; unavailable legacy identity stays null. */
+    /** Original run_id from the public claim; unavailable legacy identity stays null. */
     public readonly ?string $runId;
 
     /**
@@ -33,8 +33,12 @@ public function __construct(
         array $taskMetadata = [],
     ) {
         $this->retryInfo = ActivityRetryInfo::fromTask($attemptNumber, $taskMetadata);
-        $this->workflowId = self::receivedIdentity($taskMetadata['workflow_instance_id'] ?? null);
-        $this->runId = self::receivedIdentity($taskMetadata['workflow_run_id'] ?? null);
+        // Public claim keys take precedence, including explicit null. Retain the
+        // internal-name aliases used by local parents and 3.6.0 constructor callers.
+        $this->workflowId = self::receivedIdentity(array_key_exists('workflow_id', $taskMetadata)
+            ? $taskMetadata['workflow_id'] : ($taskMetadata['workflow_instance_id'] ?? null));
+        $this->runId = self::receivedIdentity(array_key_exists('run_id', $taskMetadata)
+            ? $taskMetadata['run_id'] : ($taskMetadata['workflow_run_id'] ?? null));
     }
 
     private static function receivedIdentity(mixed $value): ?string
diff --git a/tests/ActivityRetryInfoTest.php b/tests/ActivityRetryInfoTest.php
index f5ca185d..1fa67ac3 100644
--- a/tests/ActivityRetryInfoTest.php
+++ b/tests/ActivityRetryInfoTest.php
@@ -69,6 +69,29 @@ public function testLegacyConstructorAndServerFreeActivitiesHaveUnknownMetadata(
         self::assertNull($context->runId);
     }
 
+    public static function originalIdentities(): array
+    {
+        return [
+            'public claim' => [['workflow_id' => '0', 'run_id' => '017'], '0', '017'],
+            'legacy aliases' => [['workflow_instance_id' => 'parent', 'workflow_run_id' => 'parent-run'], 'parent', 'parent-run'],
+            'public takes precedence' => [['workflow_id' => 'original', 'run_id' => 'original-run',
+                'workflow_instance_id' => 'other', 'workflow_run_id' => 'other-run'], 'original', 'original-run'],
+            'public null remains unknown' => [['workflow_id' => null, 'run_id' => null,
+                'workflow_instance_id' => 'other', 'workflow_run_id' => 'other-run'], null, null],
+            'invalid identity remains unknown' => [['workflow_id' => 42, 'run_id' => ''], null, null],
+            'partially missing identity' => [['workflow_id' => 'original'], 'original', null],
+        ];
+    }
+
+    #[DataProvider('originalIdentities')]
+    public function testOriginalIdentityUsesThePublicClaimWithoutRetargeting(array $metadata, ?string $workflowId, ?string $runId): void
+    {
+        $context = new ActivityContext(new Client('https://server.example'), 'task', 'attempt', 'owner', 'activity', 1,
+            taskMetadata: $metadata);
+        self::assertSame($workflowId, $context->workflowId);
+        self::assertSame($runId, $context->runId);
+    }
+
     public function testInlineLocalActivityRetainsParentIdentityWithoutInventingRetryPolicy(): void
     {
         $completion = null;
@@ -114,7 +137,7 @@ public static function claimedMetadata(): array
     {
         return [
             'bounded' => [['retry_policy' => ['max_attempts' => 3, 'future' => [true, null]], 'attempt_number' => 3,
-                'workflow_instance_id' => '0', 'workflow_run_id' => '017'], true, true],
+                'workflow_id' => '0', 'run_id' => '017'], true, true],
             'absent legacy' => [[], false, null],
             'explicit root null' => [['retry_policy' => null], true, null],
             'unlimited' => [['retry_policy' => ['max_attempts' => null]], true, false],
@@ -158,7 +181,7 @@ public function testOrdinaryWorkerExposesTheReceivedClaim(array $metadata, bool
         self::assertSame($provided, $result['provided']);
         self::assertSame($metadata['retry_policy'] ?? null, $result['policy']);
         self::assertSame($last, $result['last']);
-        self::assertSame($metadata['workflow_instance_id'] ?? null, $result['workflow_id']);
-        self::assertSame($metadata['workflow_run_id'] ?? null, $result['run_id']);
+        self::assertSame($metadata['workflow_id'] ?? null, $result['workflow_id']);
+        self::assertSame($metadata['run_id'] ?? null, $result['run_id']);
     }
 }
diff --git a/tests/CooperativeRemoteActivityTest.php b/tests/CooperativeRemoteActivityTest.php
index a01dc41d..aaa9a698 100644
--- a/tests/CooperativeRemoteActivityTest.php
+++ b/tests/CooperativeRemoteActivityTest.php
@@ -295,7 +295,7 @@ public function testUserProgressIsProxiedAndResultTypesSurvive(): void
     public function testReceivedRetryAndWorkflowIdentityReachTheSupervisedCallback(): void
     {
         foreach ([[], ['attempt_number' => 3, 'retry_policy' => ['max_attempts' => 3, 'future' => [true]],
-            'workflow_instance_id' => 'workflow', 'workflow_run_id' => 'original-run']] as $metadata) {
+            'workflow_id' => 'workflow', 'run_id' => 'original-run']] as $metadata) {
             $transport = new RemoteOwnerTransport();
             $transport->taskMetadata = $metadata;
             $pids = [];
@@ -316,8 +316,8 @@ public function testReceivedRetryAndWorkflowIdentityReachTheSupervisedCallback()
             self::assertSame($metadata['retry_policy'] ?? null, $result['policy']);
             self::assertSame($metadata !== [], $result['provided']);
             self::assertSame($metadata === [] ? null : true, $result['last']);
-            self::assertSame($metadata['workflow_instance_id'] ?? null, $result['workflow_id']);
-            self::assertSame($metadata['workflow_run_id'] ?? null, $result['run_id']);
+            self::assertSame($metadata['workflow_id'] ?? null, $result['workflow_id']);
+            self::assertSame($metadata['run_id'] ?? null, $result['run_id']);
         }
     }