diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0a5ef15..1e5d02a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -25,6 +25,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - The macro implementation provides a foundation for future macro evolution in conditional specification composition
 - All implementations include comprehensive documentation and usage examples
 
+## [4.0.1] - 2026-09-19
+
+### Fixed
+- Require SpecificationCore 1.0.1, which fixes Swift 6.3+ compilation ambiguity in `FirstMatchSpec.Builder.build()`.
+
 ## [3.0.0] - 2025-11-16
 
 ### Added - Major Release Features
diff --git a/Package.swift b/Package.swift
index b6f8dc4..04962bc 100644
--- a/Package.swift
+++ b/Package.swift
@@ -23,7 +23,7 @@ let package = Package(
     ],
     dependencies: [
         // SpecificationCore: Platform-independent core functionality
-        .package(url: "https://github.com/SoundBlaster/SpecificationCore", from: "1.0.0"),
+        .package(url: "https://github.com/SoundBlaster/SpecificationCore", from: "1.0.1"),
         // Depend on the latest Swift Syntax package for macro support.
         .package(url: "https://github.com/swiftlang/swift-syntax", from: "510.0.0"),
         // Add swift-macro-testing for a simplified macro testing experience.