diff --git a/CHANGELOG.md b/CHANGELOG.md
index 902971f..47672c3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,12 @@
+## 0.2.2
+
+### 🐛 Bug Fixes
+- **Fixed Xcode 27 build failure** ("switch must be exhaustive") in the iOS and macOS plugins. The Xcode 27 SDK adds new cases to the non-frozen Foundation Models enums `Transcript.Entry` (`.reasoning`) and `Transcript.Segment` (`.attachment`, `.custom`), which broke the exhaustive `switch` statements in `serializeSegment` and `mapTranscriptEntries`.
+- Added `@unknown default` clauses to all `switch` statements over non-frozen Apple framework enums (`Transcript.Entry`, `Transcript.Segment`, and `LanguageModelSession.GenerationError`) so the plugin keeps compiling as Apple adds enum cases in future SDKs.
+
+### ✨ Improvements
+- **First-class handling of reasoning transcripts on Xcode 27+.** When built with a Swift 6.4+ toolchain (Xcode 27+), `.reasoning` transcript entries are serialized with a dedicated `reasoning` role and their segments are mapped just like other entries, and `.attachment`/`.custom` segments are serialized explicitly. This is gated behind `#if compiler(>=6.4)` so the plugin continues to build on Xcode 26 (where those cases do not exist), falling back to the `@unknown default` behavior there.
+
 ## 0.2.1
 
 ### 📚 Documentation Improvements
diff --git a/ios/Classes/FoundationModelsFrameworkPlugin.swift b/ios/Classes/FoundationModelsFrameworkPlugin.swift
index d0f4db8..30893fe 100644
--- a/ios/Classes/FoundationModelsFrameworkPlugin.swift
+++ b/ios/Classes/FoundationModelsFrameworkPlugin.swift
@@ -365,6 +365,21 @@ import AppKit
                 role = "response"
                 segmentsText = response.segments.map(serializeSegment)
                 content = segmentsText.joined(separator: "\n")
+            #if compiler(>=6.4)
+            // `.reasoning` was added to `Transcript.Entry` in the Xcode 27 / iOS 26+ SDK.
+            // Gate it on the Swift 6.4+ toolchain (Xcode 27+) so this still builds on
+            // Xcode 26, where the case does not exist; older toolchains use `@unknown default`.
+            case .reasoning(let reasoning):
+                role = "reasoning"
+                segmentsText = reasoning.segments.map(serializeSegment)
+                content = segmentsText.joined(separator: "\n")
+            #endif
+            @unknown default:
+                // Handle any further entry kinds added in future SDKs without breaking the build.
+                role = "unknown"
+                let description = String(describing: entry)
+                segmentsText = [description]
+                content = description
             }
 
             return TranscriptEntry(id: entry.id, role: role, content: content, segments: segmentsText)
@@ -378,6 +393,18 @@ import AppKit
             return textSegment.content
         case .structure(let structuredSegment):
             return String(describing: structuredSegment.content)
+        #if compiler(>=6.4)
+        // `.attachment` and `.custom` were added to `Transcript.Segment` in the
+        // Xcode 27 / iOS 26+ SDK. Gate them on the Swift 6.4+ toolchain (Xcode 27+) so
+        // this still builds on Xcode 26; older toolchains use `@unknown default`.
+        case .attachment(let attachmentSegment):
+            return String(describing: attachmentSegment)
+        case .custom(let customSegment):
+            return String(describing: customSegment)
+        #endif
+        @unknown default:
+            // Handle any further segment kinds added in future SDKs.
+            return String(describing: segment)
         }
     }
     @available(iOS 26.0, macOS 15.0, *)
@@ -430,6 +457,9 @@ import AppKit
                 return FoundationModelsError.requestFailed("Unsupported guide")
             case .unsupportedLanguageOrLocale(_):
                 return FoundationModelsError.requestFailed("Unsupported language or locale")
+            @unknown default:
+                // Handle generation error cases added in newer SDKs without breaking the build.
+                return FoundationModelsError.requestFailed("Generation failed")
             }
         }
 
diff --git a/macos/Classes/FoundationModelsFrameworkPlugin.swift b/macos/Classes/FoundationModelsFrameworkPlugin.swift
index 4d369d6..790cd4d 100644
--- a/macos/Classes/FoundationModelsFrameworkPlugin.swift
+++ b/macos/Classes/FoundationModelsFrameworkPlugin.swift
@@ -365,6 +365,21 @@ import AppKit
                 role = "response"
                 segmentsText = response.segments.map(serializeSegment)
                 content = segmentsText.joined(separator: "\n")
+            #if compiler(>=6.4)
+            // `.reasoning` was added to `Transcript.Entry` in the Xcode 27 / macOS 26+ SDK.
+            // Gate it on the Swift 6.4+ toolchain (Xcode 27+) so this still builds on
+            // Xcode 26, where the case does not exist; older toolchains use `@unknown default`.
+            case .reasoning(let reasoning):
+                role = "reasoning"
+                segmentsText = reasoning.segments.map(serializeSegment)
+                content = segmentsText.joined(separator: "\n")
+            #endif
+            @unknown default:
+                // Handle any further entry kinds added in future SDKs without breaking the build.
+                role = "unknown"
+                let description = String(describing: entry)
+                segmentsText = [description]
+                content = description
             }
 
             return TranscriptEntry(id: entry.id, role: role, content: content, segments: segmentsText)
@@ -378,6 +393,18 @@ import AppKit
             return textSegment.content
         case .structure(let structuredSegment):
             return String(describing: structuredSegment.content)
+        #if compiler(>=6.4)
+        // `.attachment` and `.custom` were added to `Transcript.Segment` in the
+        // Xcode 27 / macOS 26+ SDK. Gate them on the Swift 6.4+ toolchain (Xcode 27+) so
+        // this still builds on Xcode 26; older toolchains use `@unknown default`.
+        case .attachment(let attachmentSegment):
+            return String(describing: attachmentSegment)
+        case .custom(let customSegment):
+            return String(describing: customSegment)
+        #endif
+        @unknown default:
+            // Handle any further segment kinds added in future SDKs.
+            return String(describing: segment)
         }
     }
     @available(iOS 26.0, macOS 26.0, *)
@@ -430,6 +457,9 @@ import AppKit
                 return FoundationModelsError.requestFailed("Unsupported guide")
             case .unsupportedLanguageOrLocale(_):
                 return FoundationModelsError.requestFailed("Unsupported language or locale")
+            @unknown default:
+                // Handle generation error cases added in newer SDKs without breaking the build.
+                return FoundationModelsError.requestFailed("Generation failed")
             }
         }
 
diff --git a/pubspec.yaml b/pubspec.yaml
index ecc916d..00ac37d 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,6 +1,6 @@
 name: foundation_models_framework
 description: A Flutter package for integrating with Apple's Foundation Models framework on iOS and macOS devices. Provides session-based language model interactions with Apple Intelligence features.
-version: 0.2.1
+version: 0.2.2
 homepage: https://github.com/dmakwt/flutter_foundation_models_framework
 repository: https://github.com/dmakwt/flutter_foundation_models_framework
 issue_tracker: https://github.com/dmakwt/flutter_foundation_models_framework/issues