diff --git a/Samples/SwiftJavaExtractJNISampleApp/Sources/MySwiftLibrary/ActorProperties.swift b/Samples/SwiftJavaExtractJNISampleApp/Sources/MySwiftLibrary/ActorProperties.swift
index d5ef8ce87..d63e8a46c 100644
--- a/Samples/SwiftJavaExtractJNISampleApp/Sources/MySwiftLibrary/ActorProperties.swift
+++ b/Samples/SwiftJavaExtractJNISampleApp/Sources/MySwiftLibrary/ActorProperties.swift
@@ -27,3 +27,15 @@ public actor IdentifiedActor: ActorIdentifier {
     self.unwitnessed = identifier + 1
   }
 }
+
+public protocol SendableActorIdentifier: AnyObject, Sendable {
+  var identifier: Int64 { get }
+}
+
+public actor SendableIdentifiedActor: SendableActorIdentifier {
+  public let identifier: Int64
+
+  public init(identifier: Int64) {
+    self.identifier = identifier
+  }
+}
diff --git a/Samples/SwiftJavaExtractJNISampleApp/src/test/java/com/example/swift/ActorPropertiesTest.java b/Samples/SwiftJavaExtractJNISampleApp/src/test/java/com/example/swift/ActorPropertiesTest.java
index 37486af44..9d20c2dc2 100644
--- a/Samples/SwiftJavaExtractJNISampleApp/src/test/java/com/example/swift/ActorPropertiesTest.java
+++ b/Samples/SwiftJavaExtractJNISampleApp/src/test/java/com/example/swift/ActorPropertiesTest.java
@@ -22,6 +22,15 @@
 import static org.junit.jupiter.api.Assertions.*;
 
 public class ActorPropertiesTest {
+    @Test
+    void standardProtocolConstraintsKeepWitnessesSynchronous() {
+        try (var arena = SwiftArena.ofConfined()) {
+            SendableIdentifiedActor actor = SendableIdentifiedActor.init(42, arena);
+            long identifier = actor.getIdentifier();
+            assertEquals(42, identifier);
+        }
+    }
+
     @Test
     void nonisolatedPropertiesStaySynchronous() {
         try (var arena = SwiftArena.ofConfined()) {
diff --git a/Sources/SwiftExtract/SwiftTypes/SwiftFunctionSignature.swift b/Sources/SwiftExtract/SwiftTypes/SwiftFunctionSignature.swift
index 1e63329c8..72af981c5 100644
--- a/Sources/SwiftExtract/SwiftTypes/SwiftFunctionSignature.swift
+++ b/Sources/SwiftExtract/SwiftTypes/SwiftFunctionSignature.swift
@@ -449,7 +449,15 @@ extension SwiftFunctionSignature {
       else { return false }
       if !visited.insert(declaration.identity).inserted { return true }
       return (declaration.inheritanceTypes ?? []).allSatisfy { inherited in
-        guard let type = try? SwiftType(inherited.type, lookupContext: lookupContext) else { return false }
+        let type = try? SwiftType(inherited.type, lookupContext: lookupContext)
+        // These standard constraints do not introduce actor isolation and are
+        // absent from SwiftExtract's built-in Swift symbol table.
+        if ["AnyObject", "Swift.AnyObject", "Sendable", "Swift.Sendable"].contains(inherited.type.trimmedDescription),
+          type == nil || type?.asNominalTypeDeclaration?.moduleName == "Swift"
+        {
+          return true
+        }
+        guard let type else { return false }
         return isNonisolatedProtocol(type, visited: &visited)
       }
     }
diff --git a/Tests/JExtractSwiftTests/JNI/JNIActorPropertyTests.swift b/Tests/JExtractSwiftTests/JNI/JNIActorPropertyTests.swift
index 2cdc603e8..51b3f159b 100644
--- a/Tests/JExtractSwiftTests/JNI/JNIActorPropertyTests.swift
+++ b/Tests/JExtractSwiftTests/JNI/JNIActorPropertyTests.swift
@@ -64,4 +64,26 @@ struct JNIActorPropertyTests {
       ]
     )
   }
+
+  @Test(arguments: ["AnyObject", "Swift.AnyObject", "Sendable", "Swift.Sendable", "AnyObject, Swift.Sendable"])
+  func standardConstraintsPreserveSynchronousBindings(_ inheritance: String) throws {
+    let source = """
+      public protocol Identified: \(inheritance) { var identifier: Int64 { get } }
+      public actor Record: Identified { public let identifier: Int64 }
+      """
+    try assertOutput(
+      input: source,
+      .jni,
+      .java,
+      expectedChunks: ["public long getIdentifier() {"],
+      notExpectedChunks: ["public java.util.concurrent.CompletableFuture<java.lang.Long> getIdentifier() {"]
+    )
+    try assertOutput(
+      input: source,
+      .jni,
+      .swift,
+      expectedChunks: ["return (selfPointer$.pointee as any Identified).identifier.getJNILocalRefValue(in: environment)"],
+      notExpectedChunks: ["await selfPointer$.pointee.identifier"]
+    )
+  }
 }
diff --git a/Tests/SwiftExtractTests/ActorPropertyIsolationTests.swift b/Tests/SwiftExtractTests/ActorPropertyIsolationTests.swift
index fa4056f26..58fcb0840 100644
--- a/Tests/SwiftExtractTests/ActorPropertyIsolationTests.swift
+++ b/Tests/SwiftExtractTests/ActorPropertyIsolationTests.swift
@@ -65,6 +65,47 @@ struct ActorPropertyIsolationTests {
     }
   }
 
+  @Test(arguments: ["AnyObject", "Swift.AnyObject", "Sendable", "Swift.Sendable", "AnyObject, Swift.Sendable"])
+  func standardConstraintsPreserveSynchronousWitness(_ inheritance: String) throws {
+    let source = """
+      public protocol Identified: \(inheritance) { var identifier: Int64 { get } }
+      public actor Record: Identified { public let identifier: Int64 }
+      """
+    let result = try analyze(sources: [("/fake/Source.swift", source)], moduleName: "Test")
+    let record = try #require(result.extractedTypes.values.first { $0.swiftNominal.name == "Record" })
+    let accessor = try #require(record.variables.first { $0.name == "identifier" })
+    #expect(accessor.functionSignature.nonisolatedWitnessProtocol?.asNominalTypeDeclaration?.name == "Identified")
+    #expect(!accessor.functionSignature.isImplicitlyAsync)
+  }
+
+  @Test
+  func inheritedStandardConstraintsPreserveSynchronousWitness() throws {
+    let source = """
+      public protocol Identified: AnyObject, Sendable { var identifier: Int64 { get } }
+      public protocol InheritedIdentifier: Identified {}
+      public actor Record: InheritedIdentifier { public let identifier: Int64 }
+      """
+    let result = try analyze(sources: [("/fake/Source.swift", source)], moduleName: "Test")
+    let record = try #require(result.extractedTypes.values.first { $0.swiftNominal.name == "Record" })
+    let accessor = try #require(record.variables.first { $0.name == "identifier" })
+    #expect(accessor.functionSignature.nonisolatedWitnessProtocol?.asNominalTypeDeclaration?.name == "InheritedIdentifier")
+    #expect(!accessor.functionSignature.isImplicitlyAsync)
+  }
+
+  @Test
+  func localSendableDoesNotBypassIsolation() throws {
+    let source = """
+      @MainActor public protocol Sendable {}
+      public protocol Identified: Sendable { var identifier: Int64 { get } }
+      public actor Record: Identified { public let identifier: Int64 }
+      """
+    let result = try analyze(sources: [("/fake/Source.swift", source)], moduleName: "Test")
+    let record = try #require(result.extractedTypes.values.first { $0.swiftNominal.name == "Record" })
+    let accessor = try #require(record.variables.first { $0.name == "identifier" })
+    #expect(accessor.functionSignature.nonisolatedWitnessProtocol == nil)
+    #expect(accessor.functionSignature.isImplicitlyAsync)
+  }
+
   private func record() throws -> ExtractedNominalType {
     let result = try analyze(sources: [("/fake/Source.swift", Self.source)], moduleName: "Test")
     return try #require(result.extractedTypes.values.first { $0.swiftNominal.name == "Record" })