I figured it out. When returning a result together with a value the return definition of the perform() function needs to include IntentResult like so: // Works as described ✅ func perform() async throws -> some IntentResult & ReturnsValue<String> { return .result(value: "Some text") } Including just ReturnsValue<String> will result in the exception above and modified version of the intent will nob be picked up by the compiler. // Incorrect function annotation ❌ func perform() async throws -> some ReturnsValue<String> { return .result(value: "Some text") }