diff --git a/tests/Common/FeatureFlags/flag_evaluation_wire.inc b/tests/Common/FeatureFlags/flag_evaluation_wire.inc
index 08ef6b7f63..2a2c03e73d 100644
--- a/tests/Common/FeatureFlags/flag_evaluation_wire.inc
+++ b/tests/Common/FeatureFlags/flag_evaluation_wire.inc
@@ -92,8 +92,11 @@ try {
             $protectedBytesAbsent = $protectedBytesAbsent
                 && strpos($capture[3], 'ffe-protected-pii-canary@example.test') === false
                 && strpos($capture[3], 'ffe-context-pii-canary@example.test') === false;
-            if (strpos($capture[3], 'ffe-error-pii-canary@example.test') !== false) {
-                throw new RuntimeException('raw error text reached the payload');
+            foreach (array('ffe-error-pii-canary@example.test', 'ffe-oversized-identity-canary-',
+                'oversized-identity-context-canary@example.test') as $canary) {
+                if (strpos($capture[3], $canary) !== false) {
+                    throw new RuntimeException('omitted evaluation data reached the payload');
+                }
             }
             // Application attribution is deferred to FFL-3438/FFL-3439.
             $evaluationIdentityAbsent = $evaluationIdentityAbsent && $payload['context'] === array();
@@ -129,6 +132,23 @@ try {
     echo 'protected_subject='; var_dump($rows['protected']['targeting_key']);
     echo 'protected_context_absent='; var_dump(!isset($rows['protected']['context']['evaluation']));
     echo 'protected_raw_bytes_absent='; var_dump($protectedBytesAbsent);
+    foreach (array('oversized-identity', 'oversized-successor') as $flag) {
+        $row = $rows[$flag];
+        if ($row['evaluation_count'] !== 1 || $row['variant']['key'] !== 'blue'
+            || $row['allocation']['key'] !== 'allocation'
+            || array_key_exists('error', $row) || array_key_exists('runtime_default_used', $row)
+            || !is_int($row['timestamp']) || !is_int($row['first_evaluation'])
+            || !is_int($row['last_evaluation']) || $row['first_evaluation'] > $row['last_evaluation']) {
+            throw new RuntimeException('oversized identity or its successor lost evaluation dimensions');
+        }
+    }
+    echo 'oversized_identity_omits_identity_and_context=';
+    var_dump(!array_key_exists('targeting_key', $rows['oversized-identity'])
+        && !array_key_exists('context', $rows['oversized-identity']));
+    echo 'oversized_identity_successor_retains_context=';
+    var_dump($rows['oversized-successor']['targeting_key'] === 'normal-successor'
+        && $rows['oversized-successor']['context']['evaluation'] === array(
+            'email' => 'oversized-successor-context-canary@example.test'));
     echo 'evaluation_times_preserved=';
     var_dump($rows['timestamped']['evaluation_count'] === 2
         && $rows['timestamped']['timestamp'] === 1700000000456
@@ -186,7 +206,9 @@ try {
         $piiAbsent = true;
         foreach (array('ffe-protected-pii-canary@example.test', 'ffe-context-pii-canary@example.test',
             'ffe-consented-pii-canary@example.test', 'ffe-consented-context-canary@example.test',
-            'ffe-error-pii-canary@example.test') as $canary) {
+            'ffe-error-pii-canary@example.test', 'ffe-oversized-identity-canary-',
+            'oversized-identity-context-canary@example.test',
+            'oversized-successor-context-canary@example.test') as $canary) {
             $piiAbsent = $piiAbsent && !ffeTestStreamContains($diagnostics, $canary)
                 && strpos($stderr, $canary) === false;
         }
diff --git a/tests/Common/FeatureFlags/flag_evaluation_wire_app.php b/tests/Common/FeatureFlags/flag_evaluation_wire_app.php
index c1d9b7d77f..baf4fd6ff8 100644
--- a/tests/Common/FeatureFlags/flag_evaluation_wire_app.php
+++ b/tests/Common/FeatureFlags/flag_evaluation_wire_app.php
@@ -11,7 +11,8 @@
     'observeFullEvaluationData' => true,
     'flags' => array(),
 );
-foreach (array('consented', 'protected', 'coerced', 'empty', 'missing', 'malformed', 'hook-after-error') as $key) {
+foreach (array('consented', 'protected', 'coerced', 'empty', 'missing', 'malformed', 'hook-after-error',
+    'oversized-identity', 'oversized-successor') as $key) {
     $config['flags'][$key] = array(
         'key' => $key, 'enabled' => true, 'variationType' => 'STRING',
         'variations' => array('blue' => array('key' => 'blue', 'value' => 'blue')),
@@ -37,6 +38,22 @@
         throw new RuntimeException('assignment failed');
     }
 }
+// Exercise the public API and native bridge in one request, before any
+// explicit flush or reconnect can hide damage to the submitting connection.
+// This is deliberately above the native IPC budget, not an exact boundary test.
+foreach (array('oversized-identity' => 'ffe-oversized-identity-canary-' . str_repeat('x', 5 * 1024 * 1024),
+    'oversized-successor' => 'normal-successor') as $flag => $targetingKey) {
+    $attributes = array('email' => $flag . '-context-canary@example.test');
+    $evaluationContext = array('targetingKey' => $targetingKey, 'attributes' => $attributes);
+    if (getenv('PHP_FFE_WIRE_OPENFEATURE') === '1') {
+        $evaluationContext = new \OpenFeature\implementation\flags\EvaluationContext($targetingKey,
+            new \OpenFeature\implementation\flags\Attributes($attributes));
+    }
+    if ($client->getStringValue($flag, 'fallback', $evaluationContext) !== 'blue') {
+        throw new RuntimeException('oversized identity or its successor changed assignment');
+    }
+}
+unset($targetingKey, $evaluationContext);
 $config['observeFullEvaluationData'] = false;
 \DDTrace\Testing\ffe_load_config(json_encode($config));
 $protectedKey = 'ffe-protected-pii-canary@example.test';
diff --git a/tests/OpenFeature/flag_evaluation_openfeature_wire.phpt b/tests/OpenFeature/flag_evaluation_openfeature_wire.phpt
index 042390095d..2b9f17a695 100644
--- a/tests/OpenFeature/flag_evaluation_openfeature_wire.phpt
+++ b/tests/OpenFeature/flag_evaluation_openfeature_wire.phpt
@@ -37,6 +37,8 @@ protected_count=int(1)
 protected_subject=string(71) "sha256_2234a4963a43ffe952df4e09b1fd0d36f8b49216e5cba4182ae4d01e67cf112a"
 protected_context_absent=bool(true)
 protected_raw_bytes_absent=bool(true)
+oversized_identity_omits_identity_and_context=bool(true)
+oversized_identity_successor_retains_context=bool(true)
 evaluation_times_preserved=bool(true)
 identity_omissions_preserve_evaluations=bool(true)
 first_256_inspected=bool(true)
diff --git a/tests/api/Unit/FeatureFlags/flag_evaluation_wire.phpt b/tests/api/Unit/FeatureFlags/flag_evaluation_wire.phpt
index 264b0b8682..354ade95e2 100644
--- a/tests/api/Unit/FeatureFlags/flag_evaluation_wire.phpt
+++ b/tests/api/Unit/FeatureFlags/flag_evaluation_wire.phpt
@@ -35,6 +35,8 @@ protected_count=int(1)
 protected_subject=string(71) "sha256_2234a4963a43ffe952df4e09b1fd0d36f8b49216e5cba4182ae4d01e67cf112a"
 protected_context_absent=bool(true)
 protected_raw_bytes_absent=bool(true)
+oversized_identity_omits_identity_and_context=bool(true)
+oversized_identity_successor_retains_context=bool(true)
 evaluation_times_preserved=bool(true)
 identity_omissions_preserve_evaluations=bool(true)
 first_256_inspected=bool(true)