diff --git a/lib/JIT/Context.php b/lib/JIT/Context.php
index 79746fbc35a..bc4f6191e48 100644
--- a/lib/JIT/Context.php
+++ b/lib/JIT/Context.php
@@ -1111,6 +1111,14 @@ public function resolveFunctionProxy(string $proxyName): Call
         if (null !== $bound) {
             return $bound;
         }
+        if ($this->isUserScriptAot() && str_contains($lc, '::')) {
+            $vmOnly = self::findInternalClassMethodInVmRegistry($this, $lc);
+            if (null !== $vmOnly && !self::internalBuiltinHasJitLowering($vmOnly)) {
+                throw new \LogicException(
+                    \sprintf('%s is registered in the VM but has no JIT lowering (#36202)', $proxyName)
+                );
+            }
+        }
         $this->functionProxies[$lc] = new Call\ExternalMethod($proxyName);
 
         return $this->functionProxies[$lc];
@@ -1243,9 +1251,65 @@ private function resolveRegisteredInternalBuiltin(string $lc): ?FuncInternal
             }
         }
 
+        // Registered builtin class methods with JIT lowering — one table for VM and JIT (#36202).
+        // VM-only handlers stay on ExternalMethod until call() is implemented (helper infra).
+        if (!\PHPCompiler\AOT\ExternalMethodBind::spineChunkMode()) {
+            $vmMethod = self::findInternalClassMethodInVmRegistry($this, $lc);
+            if (null !== $vmMethod && self::internalBuiltinHasJitLowering($vmMethod)) {
+                return $vmMethod;
+            }
+        }
+
         return null;
     }
 
+    /**
+     * VM registry lookup for `Class::method` — one table for VM and JIT (#36202).
+     */
+    private static function findInternalClassMethodInVmRegistry(self $context, string $lc): ?FuncInternal
+    {
+        if (!str_contains($lc, '::')) {
+            return null;
+        }
+        [$classLc, $methodLc] = explode('::', $lc, 2);
+        $classLc = strtolower(ltrim($classLc, '\\'));
+        $methodLc = strtolower($methodLc);
+        if ('' === $classLc || '' === $methodLc) {
+            return null;
+        }
+
+        $vm = $context->runtime->vmContext;
+        while (isset($vm->classAliases[$classLc])) {
+            $classLc = $vm->classAliases[$classLc];
+        }
+        if (!isset($vm->classes[$classLc])) {
+            return null;
+        }
+
+        $entry = $vm->classes[$classLc];
+        if (!isset($entry->methods[$methodLc])) {
+            return null;
+        }
+
+        $method = $entry->methods[$methodLc];
+        if (!$method instanceof FuncInternal) {
+            return null;
+        }
+
+        return $method;
+    }
+
+    /** True when an Internal / VmClassMethod overrides {@see VmClassMethod::call()} for JIT. */
+    private static function internalBuiltinHasJitLowering(FuncInternal $method): bool
+    {
+        if (!$method instanceof \PHPCompiler\VM\Builtin\VmClassMethod) {
+            return true;
+        }
+        $ref = new \ReflectionMethod($method, 'call');
+
+        return \PHPCompiler\VM\Builtin\VmClassMethod::class !== $ref->getDeclaringClass()->getName();
+    }
+
     /**
      * Internal builtins safe to resolve from Runtime modules during SPINE_CHUNK chunk emits.
      *
diff --git a/test/unit/ExternalMethodBindTest.php b/test/unit/ExternalMethodBindTest.php
index da69aacf75c..22a33ee1533 100644
--- a/test/unit/ExternalMethodBindTest.php
+++ b/test/unit/ExternalMethodBindTest.php
@@ -6,6 +6,7 @@
 
 use PHPCompiler\AOT\ExternalMethodBind;
 use PHPCompiler\JIT\Call\ExternalMethod;
+use PHPCompiler\JIT\UserScriptAotEnv;
 use PHPUnit\Framework\TestCase;
 
 /**
@@ -23,6 +24,9 @@ protected function tearDown(): void
         unset($_ENV[ExternalMethodBind::ENV_MANIFEST], $_SERVER[ExternalMethodBind::ENV_MANIFEST]);
         putenv('PHP_COMPILER_HELPER_RUNTIME_O');
         unset($_ENV['PHP_COMPILER_HELPER_RUNTIME_O'], $_SERVER['PHP_COMPILER_HELPER_RUNTIME_O']);
+        putenv('PHP_COMPILER_AOT_USER_SCRIPT');
+        unset($_ENV['PHP_COMPILER_AOT_USER_SCRIPT'], $_SERVER['PHP_COMPILER_AOT_USER_SCRIPT']);
+        UserScriptAotEnv::resetLatchForTest();
         ExternalMethodBind::resetManifestForTests();
         parent::tearDown();
     }
@@ -198,6 +202,44 @@ public function testTryBindFromChunkManifestBitcode(): void
         $this->assertInstanceOf(\PHPLLVM\Type::class, $bound->argTypes[0]);
     }
 
+    /**
+     * User-script AOT must not silently null a registered-but-unlowered builtin method (#36202).
+     */
+    public function testUserScriptAotRejectsUnloweredVmClassMethod(): void
+    {
+        putenv('PHP_COMPILER_AOT_USER_SCRIPT=1');
+        $_ENV['PHP_COMPILER_AOT_USER_SCRIPT'] = '1';
+        $runtime = new Runtime(Runtime::MODE_AOT);
+        $ctx = new JIT\Context($runtime, JIT\Builtin::LOAD_TYPE_STANDALONE);
+        $this->expectException(\LogicException::class);
+        $this->expectExceptionMessage('datetime::__serialize');
+        $ctx->resolveFunctionProxy('datetime::__serialize');
+    }
+
+    /**
+     * VM-only class methods keep ExternalMethod stubs outside user-script AOT (#36202).
+     */
+    public function testVmOnlyClassMethodStaysExternalMethodOutsideUserScript(): void
+    {
+        $runtime = new Runtime(Runtime::MODE_AOT);
+        $ctx = new JIT\Context($runtime, JIT\Builtin::LOAD_TYPE_STANDALONE);
+        $proxy = $ctx->resolveFunctionProxy('datetime::__serialize');
+        $this->assertInstanceOf(ExternalMethod::class, $proxy);
+    }
+
+    /**
+     * Spine chunk keeps cross-TU class methods on ExternalMethod until manifest bind (#24429).
+     */
+    public function testSpineChunkSkipsVmRegistryClassMethodLookup(): void
+    {
+        putenv(ExternalMethodBind::ENV_SPINE_CHUNK.'=1');
+        $_ENV[ExternalMethodBind::ENV_SPINE_CHUNK] = '1';
+        $runtime = new Runtime(Runtime::MODE_AOT);
+        $ctx = new JIT\Context($runtime, JIT\Builtin::LOAD_TYPE_STANDALONE);
+        $proxy = $ctx->resolveFunctionProxy('datetime::__serialize');
+        $this->assertInstanceOf(ExternalMethod::class, $proxy);
+    }
+
     /**
      * Consumer chunk may bind symbols from multiple producer manifests (#36155 Phase C).
      */