From 0b24f5ac2240b43b3a7057e0d1684a278349684d Mon Sep 17 00:00:00 2001
From: Paul Beusterien <paulbeusterien@google.com>
Date: Mon, 24 Nov 2025 18:11:47 -0800
Subject: [PATCH 01/10] Implement TODOs and add tests

---
 .../Types/Public/Generable/ModelOutput.swift  |  26 +-
 .../Unit/Types/Generable/GenerableTests.swift | 267 ++++++++++++++++--
 2 files changed, 258 insertions(+), 35 deletions(-)

diff --git a/FirebaseAI/Sources/Types/Public/Generable/ModelOutput.swift b/FirebaseAI/Sources/Types/Public/Generable/ModelOutput.swift
index 36d3626dde5..25f2cd86cb6 100644
--- a/FirebaseAI/Sources/Types/Public/Generable/ModelOutput.swift
+++ b/FirebaseAI/Sources/Types/Public/Generable/ModelOutput.swift
@@ -146,7 +146,7 @@ public struct ModelOutput: Sendable, Generable {
   /// Reads a top level, concrete partially `Generable` type from a named property.
   public func value<Value>(_ type: Value.Type = Value.self) throws -> Value
     where Value: ConvertibleFromModelOutput {
-    fatalError("`ModelOutput.value(_:)` is not implemented.")
+    return try Value(self)
   }
 
   /// Reads a concrete `Generable` type from named property.
@@ -154,12 +154,10 @@ public struct ModelOutput: Sendable, Generable {
                            forProperty property: String) throws -> Value
     where Value: ConvertibleFromModelOutput {
     guard case let .structure(properties, _) = kind else {
-      // TODO: Throw an error instead
-      fatalError("Attempting to access a property on a non-object ModelOutput.")
+      throw DecodingError.notAStructure
     }
     guard let value = properties[property] else {
-      // TODO: Throw an error instead
-      fatalError("Property '\(property)' not found in model output.")
+      throw DecodingError.missingProperty(name: property)
     }
 
     return try Value(value)
@@ -170,8 +168,7 @@ public struct ModelOutput: Sendable, Generable {
                            forProperty property: String) throws -> Value?
     where Value: ConvertibleFromModelOutput {
     guard case let .structure(properties, _) = kind else {
-      // TODO: Throw an error instead
-      fatalError("Attempting to access a property on a non-object ModelOutput.")
+      throw DecodingError.notAStructure
     }
     guard let value = properties[property] else {
       return nil
@@ -181,6 +178,21 @@ public struct ModelOutput: Sendable, Generable {
   }
 }
 
+@available(iOS 15.0, macOS 12.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
+public extension ModelOutput {
+  /// An error that occurs when decoding a value from `ModelOutput`.
+  enum DecodingError: Error {
+    /// A required property was not found in the `ModelOutput`.
+    case missingProperty(name: String)
+
+    /// A property was accessed on a `ModelOutput` that is not a structure.
+    case notAStructure
+
+    /// The type of a property in the `ModelOutput` did not match the expected type.
+    case typeMismatch(expected: Any.Type, actual: Any.Type)
+  }
+}
+
 @available(iOS 15.0, macOS 12.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
 public extension ModelOutput {
   /// A representation of the different types of content that can be stored in `ModelOutput`.
diff --git a/FirebaseAI/Tests/Unit/Types/Generable/GenerableTests.swift b/FirebaseAI/Tests/Unit/Types/Generable/GenerableTests.swift
index 365403709ea..f72cc988044 100644
--- a/FirebaseAI/Tests/Unit/Types/Generable/GenerableTests.swift
+++ b/FirebaseAI/Tests/Unit/Types/Generable/GenerableTests.swift
@@ -12,14 +12,83 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-import FirebaseAILogic
+@testable import FirebaseAILogic
 import Testing
 
 struct GenerableTests {
-  @available(iOS 15.0, macOS 12.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
-  @Test func initializeGenerableTypeFromModelOutput() throws {
+  @Test
+  func initializeGenerableTypeFromModelOutput() throws {
+    let addressProperties: [(String, any ConvertibleToModelOutput)] =
+      [("street", "123 Main St"), ("city", "Anytown"), ("zipCode", "12345")]
+    let addressModelOutput = ModelOutput(
+      properties: addressProperties, uniquingKeysWith: { _, second in second }
+    )
+    let properties: [(String, any ConvertibleToModelOutput)] =
+      [("firstName", "John"), ("lastName", "Doe"), ("age", 40), ("address", addressModelOutput)]
+    let modelOutput = ModelOutput(
+      properties: properties, uniquingKeysWith: { _, second in second }
+    )
+
+    let person = try Person(modelOutput)
+
+    #expect(person.firstName == "John")
+    #expect(person.lastName == "Doe")
+    #expect(person.age == 40)
+    #expect(person.address.street == "123 Main St")
+    #expect(person.address.city == "Anytown")
+    #expect(person.address.zipCode == "12345")
+  }
+
+  @Test
+  func initializeGenerableWithMissingProperty() throws {
+    let properties: [(String, any ConvertibleToModelOutput)] =
+      [("firstName", "John"), ("age", 40)]
+    let modelOutput = ModelOutput(
+      properties: properties, uniquingKeysWith: { _, second in second }
+    )
+
+    #expect(throws: ModelOutput.DecodingError.self) {
+      _ = try Person(modelOutput)
+    }
+  }
+
+  @Test
+  func initializeGenerableFromNonStructure() throws {
+    let modelOutput = ModelOutput("not a structure")
+
+    #expect(throws: ModelOutput.DecodingError.self) {
+      _ = try Person(modelOutput)
+    }
+  }
+
+  @Test
+  func initializeGenerableWithTypeMismatch() throws {
+    let properties: [(String, any ConvertibleToModelOutput)] =
+      [("firstName", "John"), ("lastName", "Doe"), ("age", "forty")]
+    let modelOutput = ModelOutput(
+      properties: properties, uniquingKeysWith: { _, second in second }
+    )
+
+    #expect(throws: ModelOutput.DecodingError.self) {
+      _ = try Person(modelOutput)
+    }
+  }
+
+  @Test
+  func initializeGenerableWithExtraProperties() throws {
+    let addressProperties: [(String, any ConvertibleToModelOutput)] =
+      [("street", "123 Main St"), ("city", "Anytown"), ("zipCode", "12345")]
+    let addressModelOutput = ModelOutput(
+      properties: addressProperties, uniquingKeysWith: { _, second in second }
+    )
     let properties: [(String, any ConvertibleToModelOutput)] =
-      [("firstName", "John"), ("lastName", "Doe"), ("age", 40)]
+      [
+        ("firstName", "John"),
+        ("lastName", "Doe"),
+        ("age", 40),
+        ("address", addressModelOutput),
+        ("country", "USA"),
+      ]
     let modelOutput = ModelOutput(
       properties: properties, uniquingKeysWith: { _, second in second }
     )
@@ -29,11 +98,45 @@ struct GenerableTests {
     #expect(person.firstName == "John")
     #expect(person.lastName == "Doe")
     #expect(person.age == 40)
+    #expect(person.address.street == "123 Main St")
+    #expect(person.address.city == "Anytown")
+    #expect(person.address.zipCode == "12345")
   }
 
-  @available(iOS 15.0, macOS 12.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
-  @Test func convertGenerableTypeToModelOutput() throws {
-    let person = Person(firstName: "Jane", middleName: "Marie", lastName: "Smith", age: 32)
+  @Test
+  func initializeGenerableWithMissingOptionalProperty() throws {
+    let addressProperties: [(String, any ConvertibleToModelOutput)] =
+      [("street", "123 Main St"), ("city", "Anytown"), ("zipCode", "12345")]
+    let addressModelOutput = ModelOutput(
+      properties: addressProperties, uniquingKeysWith: { _, second in second }
+    )
+    let properties: [(String, any ConvertibleToModelOutput)] =
+      [("firstName", "John"), ("lastName", "Doe"), ("age", 40), ("address", addressModelOutput)]
+    let modelOutput = ModelOutput(
+      properties: properties, uniquingKeysWith: { _, second in second }
+    )
+
+    let person = try Person(modelOutput)
+
+    #expect(person.firstName == "John")
+    #expect(person.lastName == "Doe")
+    #expect(person.age == 40)
+    #expect(person.middleName == nil)
+    #expect(person.address.street == "123 Main St")
+    #expect(person.address.city == "Anytown")
+    #expect(person.address.zipCode == "12345")
+  }
+
+  @Test
+  func convertGenerableTypeToModelOutput() throws {
+    let address = Address(street: "456 Oak Ave", city: "Someplace", zipCode: "54321")
+    let person = Person(
+      firstName: "Jane",
+      middleName: "Marie",
+      lastName: "Smith",
+      age: 32,
+      address: address
+    )
 
     let modelOutput = person.modelOutput
 
@@ -69,9 +172,82 @@ struct GenerableTests {
     }
     #expect(Int(age) == person.age)
     #expect(try modelOutput.value(forProperty: "age") == person.age)
-    // TODO: Implement `ModelOutput.value(_:)` and uncomment
-    // #expect(try modelOutput.value() == person)
-    #expect(orderedKeys == ["firstName", "middleName", "lastName", "age"])
+    let addressProperty: Address = try modelOutput.value(forProperty: "address")
+    #expect(addressProperty == person.address)
+    #expect(try modelOutput.value() == person)
+    #expect(orderedKeys == ["firstName", "middleName", "lastName", "age", "address"])
+  }
+
+  @Test
+  func convertGenerableWithNilOptionalPropertyToModelOutput() throws {
+    let address = Address(street: "789 Pine Ln", city: "Nowhere", zipCode: "00000")
+    let person = Person(
+      firstName: "Jane",
+      middleName: nil,
+      lastName: "Smith",
+      age: 32,
+      address: address
+    )
+
+    let modelOutput = person.modelOutput
+
+    guard case let .structure(properties, orderedKeys) = modelOutput.kind else {
+      Issue.record("Model output is not a structure.")
+      return
+    }
+
+    #expect(properties["middleName"] == nil)
+    #expect(orderedKeys == ["firstName", "lastName", "age", "address"])
+  }
+
+  @Test
+  func initializeWithNestedGenerable() throws {
+    let addressProperties: [(String, any ConvertibleToModelOutput)] =
+      [("street", "123 Main St"), ("city", "Anytown"), ("zipCode", "12345")]
+    let addressModelOutput = ModelOutput(
+      properties: addressProperties, uniquingKeysWith: { _, second in second }
+    )
+    let properties: [(String, any ConvertibleToModelOutput)] =
+      [("firstName", "John"), ("lastName", "Doe"), ("age", 40), ("address", addressModelOutput)]
+    let modelOutput = ModelOutput(
+      properties: properties, uniquingKeysWith: { _, second in second }
+    )
+
+    let person = try Person(modelOutput)
+
+    #expect(person.address.street == "123 Main St")
+    #expect(person.address.city == "Anytown")
+    #expect(person.address.zipCode == "12345")
+  }
+
+  @Test
+  func testPersonJSONSchema() throws {
+    let schema = Person.jsonSchema
+    guard case let .object(_, _, properties) = schema.kind else {
+      Issue.record("Schema kind is not an object.")
+      return
+    }
+    #expect(properties.count == 5)
+
+    let firstName = try #require(properties.first { $0.name == "firstName" })
+    #expect(ObjectIdentifier(firstName.type) == ObjectIdentifier(String.self))
+    #expect(firstName.isOptional == false)
+
+    let middleName = try #require(properties.first { $0.name == "middleName" })
+    #expect(ObjectIdentifier(middleName.type) == ObjectIdentifier(String.self))
+    #expect(middleName.isOptional == true)
+
+    let lastName = try #require(properties.first { $0.name == "lastName" })
+    #expect(ObjectIdentifier(lastName.type) == ObjectIdentifier(String.self))
+    #expect(lastName.isOptional == false)
+
+    let age = try #require(properties.first { $0.name == "age" })
+    #expect(ObjectIdentifier(age.type) == ObjectIdentifier(Int.self))
+    #expect(age.isOptional == false)
+
+    let address = try #require(properties.first { $0.name == "address" })
+    #expect(ObjectIdentifier(address.type) == ObjectIdentifier(Address.self))
+    #expect(address.isOptional == false)
   }
 }
 
@@ -82,6 +258,7 @@ struct Person: Equatable {
   let middleName: String?
   let lastName: String
   let age: Int
+  let address: Address
 
   nonisolated static var jsonSchema: FirebaseAILogic.JSONSchema {
     FirebaseAILogic.JSONSchema(
@@ -91,6 +268,7 @@ struct Person: Equatable {
         FirebaseAILogic.JSONSchema.Property(name: "middleName", type: String?.self),
         FirebaseAILogic.JSONSchema.Property(name: "lastName", type: String.self),
         FirebaseAILogic.JSONSchema.Property(name: "age", type: Int.self),
+        FirebaseAILogic.JSONSchema.Property(name: "address", type: Address.self),
       ]
     )
   }
@@ -101,6 +279,7 @@ struct Person: Equatable {
     addProperty(name: "middleName", value: middleName)
     addProperty(name: "lastName", value: lastName)
     addProperty(name: "age", value: age)
+    addProperty(name: "address", value: address)
     return ModelOutput(
       properties: properties,
       uniquingKeysWith: { _, second in
@@ -118,24 +297,56 @@ struct Person: Equatable {
   }
 }
 
-#if compiler(>=6.2)
-  @available(iOS 15.0, macOS 12.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
-  extension Person: nonisolated FirebaseAILogic.Generable {
-    nonisolated init(_ content: FirebaseAILogic.ModelOutput) throws {
-      firstName = try content.value(forProperty: "firstName")
-      middleName = try content.value(forProperty: "middleName")
-      lastName = try content.value(forProperty: "lastName")
-      age = try content.value(forProperty: "age")
-    }
+@available(iOS 15.0, macOS 12.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
+extension Person: nonisolated FirebaseAILogic.Generable {
+  nonisolated init(_ content: FirebaseAILogic.ModelOutput) throws {
+    firstName = try content.value(forProperty: "firstName")
+    middleName = try content.value(forProperty: "middleName")
+    lastName = try content.value(forProperty: "lastName")
+    age = try content.value(forProperty: "age")
+    address = try content.value(forProperty: "address")
   }
-#else
-  @available(iOS 15.0, macOS 12.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
-  extension Person: FirebaseAILogic.Generable {
-    nonisolated init(_ content: FirebaseAILogic.ModelOutput) throws {
-      firstName = try content.value(forProperty: "firstName")
-      middleName = try content.value(forProperty: "middleName")
-      lastName = try content.value(forProperty: "lastName")
-      age = try content.value(forProperty: "age")
+}
+
+@available(iOS 15.0, macOS 12.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
+struct Address: Equatable {
+  let street: String
+  let city: String
+  let zipCode: String
+}
+
+@available(iOS 15.0, macOS 12.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
+extension Address: nonisolated FirebaseAILogic.Generable {
+  nonisolated static var jsonSchema: FirebaseAILogic.JSONSchema {
+    FirebaseAILogic.JSONSchema(
+      type: Self.self,
+      properties: [
+        FirebaseAILogic.JSONSchema.Property(name: "street", type: String.self),
+        FirebaseAILogic.JSONSchema.Property(name: "city", type: String.self),
+        FirebaseAILogic.JSONSchema.Property(name: "zipCode", type: String.self),
+      ]
+    )
+  }
+
+  nonisolated var modelOutput: FirebaseAILogic.ModelOutput {
+    var properties = [(name: String, value: any FirebaseAILogic.ConvertibleToModelOutput)]()
+    addProperty(name: "street", value: street)
+    addProperty(name: "city", value: city)
+    addProperty(name: "zipCode", value: zipCode)
+    return ModelOutput(
+      properties: properties,
+      uniquingKeysWith: { _, second in
+        second
+      }
+    )
+    func addProperty(name: String, value: some FirebaseAILogic.Generable) {
+      properties.append((name, value))
     }
   }
-#endif
+
+  nonisolated init(_ content: FirebaseAILogic.ModelOutput) throws {
+    street = try content.value(forProperty: "street")
+    city = try content.value(forProperty: "city")
+    zipCode = try content.value(forProperty: "zipCode")
+  }
+}

From a6d4a83862aa412ecc555e2731b1ab27348e0964 Mon Sep 17 00:00:00 2001
From: Paul Beusterien <paulbeusterien@google.com>
Date: Mon, 24 Nov 2025 18:50:04 -0800
Subject: [PATCH 02/10] review

---
 .../Types/Public/Generable/ModelOutput.swift  |  3 --
 .../Unit/Types/Generable/GenerableTests.swift | 54 +++++--------------
 2 files changed, 13 insertions(+), 44 deletions(-)

diff --git a/FirebaseAI/Sources/Types/Public/Generable/ModelOutput.swift b/FirebaseAI/Sources/Types/Public/Generable/ModelOutput.swift
index 25f2cd86cb6..f48e2f82491 100644
--- a/FirebaseAI/Sources/Types/Public/Generable/ModelOutput.swift
+++ b/FirebaseAI/Sources/Types/Public/Generable/ModelOutput.swift
@@ -191,10 +191,7 @@ public extension ModelOutput {
     /// The type of a property in the `ModelOutput` did not match the expected type.
     case typeMismatch(expected: Any.Type, actual: Any.Type)
   }
-}
 
-@available(iOS 15.0, macOS 12.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
-public extension ModelOutput {
   /// A representation of the different types of content that can be stored in `ModelOutput`.
   ///
   /// `Kind` represents the various types of JSON-compatible data that can be held within a
diff --git a/FirebaseAI/Tests/Unit/Types/Generable/GenerableTests.swift b/FirebaseAI/Tests/Unit/Types/Generable/GenerableTests.swift
index f72cc988044..e85ca355e06 100644
--- a/FirebaseAI/Tests/Unit/Types/Generable/GenerableTests.swift
+++ b/FirebaseAI/Tests/Unit/Types/Generable/GenerableTests.swift
@@ -200,26 +200,6 @@ struct GenerableTests {
     #expect(orderedKeys == ["firstName", "lastName", "age", "address"])
   }
 
-  @Test
-  func initializeWithNestedGenerable() throws {
-    let addressProperties: [(String, any ConvertibleToModelOutput)] =
-      [("street", "123 Main St"), ("city", "Anytown"), ("zipCode", "12345")]
-    let addressModelOutput = ModelOutput(
-      properties: addressProperties, uniquingKeysWith: { _, second in second }
-    )
-    let properties: [(String, any ConvertibleToModelOutput)] =
-      [("firstName", "John"), ("lastName", "Doe"), ("age", 40), ("address", addressModelOutput)]
-    let modelOutput = ModelOutput(
-      properties: properties, uniquingKeysWith: { _, second in second }
-    )
-
-    let person = try Person(modelOutput)
-
-    #expect(person.address.street == "123 Main St")
-    #expect(person.address.city == "Anytown")
-    #expect(person.address.zipCode == "12345")
-  }
-
   @Test
   func testPersonJSONSchema() throws {
     let schema = Person.jsonSchema
@@ -274,26 +254,20 @@ struct Person: Equatable {
   }
 
   nonisolated var modelOutput: FirebaseAILogic.ModelOutput {
-    var properties = [(name: String, value: any FirebaseAILogic.ConvertibleToModelOutput)]()
-    addProperty(name: "firstName", value: firstName)
-    addProperty(name: "middleName", value: middleName)
-    addProperty(name: "lastName", value: lastName)
-    addProperty(name: "age", value: age)
-    addProperty(name: "address", value: address)
+    var properties: [(name: String, value: any FirebaseAILogic.ConvertibleToModelOutput)] = []
+    properties.append(("firstName", firstName))
+    if let middleName {
+      properties.append(("middleName", middleName))
+    }
+    properties.append(("lastName", lastName))
+    properties.append(("age", age))
+    properties.append(("address", address))
     return ModelOutput(
       properties: properties,
       uniquingKeysWith: { _, second in
         second
       }
     )
-    func addProperty(name: String, value: some FirebaseAILogic.Generable) {
-      properties.append((name, value))
-    }
-    func addProperty(name: String, value: (some FirebaseAILogic.Generable)?) {
-      if let value {
-        properties.append((name, value))
-      }
-    }
   }
 }
 
@@ -329,19 +303,17 @@ extension Address: nonisolated FirebaseAILogic.Generable {
   }
 
   nonisolated var modelOutput: FirebaseAILogic.ModelOutput {
-    var properties = [(name: String, value: any FirebaseAILogic.ConvertibleToModelOutput)]()
-    addProperty(name: "street", value: street)
-    addProperty(name: "city", value: city)
-    addProperty(name: "zipCode", value: zipCode)
+    let properties: [(name: String, value: any FirebaseAILogic.ConvertibleToModelOutput)] = [
+      ("street", street),
+      ("city", city),
+      ("zipCode", zipCode),
+    ]
     return ModelOutput(
       properties: properties,
       uniquingKeysWith: { _, second in
         second
       }
     )
-    func addProperty(name: String, value: some FirebaseAILogic.Generable) {
-      properties.append((name, value))
-    }
   }
 
   nonisolated init(_ content: FirebaseAILogic.ModelOutput) throws {

From ef9f72c1cc1e1d8dff97a1edfe0392c71078e204 Mon Sep 17 00:00:00 2001
From: Paul Beusterien <paulbeusterien@google.com>
Date: Tue, 25 Nov 2025 09:29:06 -0800
Subject: [PATCH 03/10] error context

---
 .../Types/Public/Generable/ModelOutput.swift  | 51 +++++++++++++++++--
 .../Unit/Types/Generable/GenerableTests.swift | 21 ++++++--
 2 files changed, 65 insertions(+), 7 deletions(-)

diff --git a/FirebaseAI/Sources/Types/Public/Generable/ModelOutput.swift b/FirebaseAI/Sources/Types/Public/Generable/ModelOutput.swift
index f48e2f82491..ac249ede6b9 100644
--- a/FirebaseAI/Sources/Types/Public/Generable/ModelOutput.swift
+++ b/FirebaseAI/Sources/Types/Public/Generable/ModelOutput.swift
@@ -16,7 +16,7 @@
 ///
 /// Model output may contain a single value, an array, or key-value pairs with unique keys.
 @available(iOS 15.0, macOS 12.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
-public struct ModelOutput: Sendable, Generable {
+public struct ModelOutput: Sendable, Generable, CustomDebugStringConvertible {
   /// The kind representation of this model output.
   ///
   /// This property provides access to the content in a strongly-typed enum representation,
@@ -70,6 +70,10 @@ public struct ModelOutput: Sendable, Generable {
   /// A representation of this instance.
   public var modelOutput: ModelOutput { self }
 
+  public var debugDescription: String {
+    return kind.debugDescription
+  }
+
   /// Creates model output representing a structure with the properties you specify.
   ///
   /// The order of properties is important. For ``Generable`` types, the order must match the order
@@ -181,7 +185,7 @@ public struct ModelOutput: Sendable, Generable {
 @available(iOS 15.0, macOS 12.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
 public extension ModelOutput {
   /// An error that occurs when decoding a value from `ModelOutput`.
-  enum DecodingError: Error {
+  enum DecodingError: Error, CustomDebugStringConvertible {
     /// A required property was not found in the `ModelOutput`.
     case missingProperty(name: String)
 
@@ -189,14 +193,31 @@ public extension ModelOutput {
     case notAStructure
 
     /// The type of a property in the `ModelOutput` did not match the expected type.
-    case typeMismatch(expected: Any.Type, actual: Any.Type)
+    case typeMismatch(context: Context)
+
+    /// The context for a decoding error.
+    public struct Context {
+      /// A description of the error.
+      public let debugDescription: String
+    }
+
+    public var debugDescription: String {
+      switch self {
+      case let .missingProperty(name):
+        return "Missing property: \(name)"
+      case .notAStructure:
+        return "Not a structure"
+      case let .typeMismatch(context):
+        return context.debugDescription
+      }
+    }
   }
 
   /// A representation of the different types of content that can be stored in `ModelOutput`.
   ///
   /// `Kind` represents the various types of JSON-compatible data that can be held within a
   /// ``ModelOutput`` instance, including primitive types, arrays, and structured objects.
-  enum Kind: Sendable {
+  enum Kind: Sendable, CustomDebugStringConvertible {
     /// Represents a null value.
     case null
 
@@ -221,5 +242,27 @@ public extension ModelOutput {
     ///   - properties: A dictionary mapping string keys to ``ModelOutput`` values.
     ///   - orderedKeys: An array of keys that specifies the order of properties.
     case structure(properties: [String: ModelOutput], orderedKeys: [String])
+
+    public var debugDescription: String {
+      switch self {
+      case .null:
+        return "null"
+      case let .bool(value):
+        return String(describing: value)
+      case let .number(value):
+        return String(describing: value)
+      case let .string(value):
+        return #""\#(value)""#
+      case let .array(elements):
+        let descriptions = elements.map { $0.debugDescription }
+        return "[\(descriptions.joined(separator: ", "))]"
+      case let .structure(properties, orderedKeys):
+        let descriptions = orderedKeys.compactMap { key -> String? in
+          guard let value = properties[key] else { return nil }
+          return #""\#(key)": \#(value.debugDescription)"#
+        }
+        return "{\(descriptions.joined(separator: ", "))}"
+      }
+    }
   }
 }
diff --git a/FirebaseAI/Tests/Unit/Types/Generable/GenerableTests.swift b/FirebaseAI/Tests/Unit/Types/Generable/GenerableTests.swift
index e85ca355e06..e3960688e20 100644
--- a/FirebaseAI/Tests/Unit/Types/Generable/GenerableTests.swift
+++ b/FirebaseAI/Tests/Unit/Types/Generable/GenerableTests.swift
@@ -47,8 +47,13 @@ struct GenerableTests {
       properties: properties, uniquingKeysWith: { _, second in second }
     )
 
-    #expect(throws: ModelOutput.DecodingError.self) {
+    do {
       _ = try Person(modelOutput)
+      Issue.record("Did not throw an error.")
+    } catch let ModelOutput.DecodingError.missingProperty(name) {
+      #expect(name == "lastName")
+    } catch {
+      Issue.record("Threw an unexpected error: \(error)")
     }
   }
 
@@ -56,8 +61,13 @@ struct GenerableTests {
   func initializeGenerableFromNonStructure() throws {
     let modelOutput = ModelOutput("not a structure")
 
-    #expect(throws: ModelOutput.DecodingError.self) {
+    do {
       _ = try Person(modelOutput)
+      Issue.record("Did not throw an error.")
+    } catch ModelOutput.DecodingError.notAStructure {
+      // Expected error
+    } catch {
+      Issue.record("Threw an unexpected error: \(error)")
     }
   }
 
@@ -69,8 +79,13 @@ struct GenerableTests {
       properties: properties, uniquingKeysWith: { _, second in second }
     )
 
-    #expect(throws: ModelOutput.DecodingError.self) {
+    do {
       _ = try Person(modelOutput)
+      Issue.record("Did not throw an error.")
+    } catch let ModelOutput.DecodingError.typeMismatch(context) {
+      #expect(context.debugDescription.contains("ModelOutput does not contain Int."))
+    } catch {
+      Issue.record("Threw an unexpected error: \(error)")
     }
   }
 

From 9b2d5e04b51b02233ab799d320d615911e421ef4 Mon Sep 17 00:00:00 2001
From: Paul Beusterien <paulbeusterien@google.com>
Date: Tue, 25 Nov 2025 09:37:10 -0800
Subject: [PATCH 04/10] data corrupted errors

---
 .../Types/Public/Generable/ModelOutput.swift   |  5 +++++
 .../Unit/Types/Generable/GenerableTests.swift  | 18 ++++++++++++++++++
 2 files changed, 23 insertions(+)

diff --git a/FirebaseAI/Sources/Types/Public/Generable/ModelOutput.swift b/FirebaseAI/Sources/Types/Public/Generable/ModelOutput.swift
index ac249ede6b9..153407c8eb6 100644
--- a/FirebaseAI/Sources/Types/Public/Generable/ModelOutput.swift
+++ b/FirebaseAI/Sources/Types/Public/Generable/ModelOutput.swift
@@ -195,6 +195,9 @@ public extension ModelOutput {
     /// The type of a property in the `ModelOutput` did not match the expected type.
     case typeMismatch(context: Context)
 
+    /// The data is corrupted or invalid.
+    case dataCorrupted(context: Context)
+
     /// The context for a decoding error.
     public struct Context {
       /// A description of the error.
@@ -209,6 +212,8 @@ public extension ModelOutput {
         return "Not a structure"
       case let .typeMismatch(context):
         return context.debugDescription
+      case let .dataCorrupted(context):
+        return context.debugDescription
       }
     }
   }
diff --git a/FirebaseAI/Tests/Unit/Types/Generable/GenerableTests.swift b/FirebaseAI/Tests/Unit/Types/Generable/GenerableTests.swift
index e3960688e20..dd83cbd474b 100644
--- a/FirebaseAI/Tests/Unit/Types/Generable/GenerableTests.swift
+++ b/FirebaseAI/Tests/Unit/Types/Generable/GenerableTests.swift
@@ -89,6 +89,24 @@ struct GenerableTests {
     }
   }
 
+  @Test
+  func initializeGenerableWithLossyNumericConversion() throws {
+    let properties: [(String, any ConvertibleToModelOutput)] =
+      [("firstName", "John"), ("lastName", "Doe"), ("age", 40.5)]
+    let modelOutput = ModelOutput(
+      properties: properties, uniquingKeysWith: { _, second in second }
+    )
+
+    do {
+      _ = try Person(modelOutput)
+      Issue.record("Did not throw an error.")
+    } catch let ModelOutput.DecodingError.dataCorrupted(context) {
+      #expect(context.debugDescription.contains("ModelOutput cannot be represented as Int."))
+    } catch {
+      Issue.record("Threw an unexpected error: \(error)")
+    }
+  }
+
   @Test
   func initializeGenerableWithExtraProperties() throws {
     let addressProperties: [(String, any ConvertibleToModelOutput)] =

From 46fd850a44d9419d08b5be7f96b47b6168af0afd Mon Sep 17 00:00:00 2001
From: Paul Beusterien <paulbeusterien@google.com>
Date: Tue, 25 Nov 2025 11:45:59 -0800
Subject: [PATCH 05/10] Fix tests after rebase

---
 FirebaseAI/Tests/Unit/Types/Generable/GenerableTests.swift | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/FirebaseAI/Tests/Unit/Types/Generable/GenerableTests.swift b/FirebaseAI/Tests/Unit/Types/Generable/GenerableTests.swift
index dd83cbd474b..8c633fbf321 100644
--- a/FirebaseAI/Tests/Unit/Types/Generable/GenerableTests.swift
+++ b/FirebaseAI/Tests/Unit/Types/Generable/GenerableTests.swift
@@ -82,8 +82,9 @@ struct GenerableTests {
     do {
       _ = try Person(modelOutput)
       Issue.record("Did not throw an error.")
-    } catch let ModelOutput.DecodingError.typeMismatch(context) {
-      #expect(context.debugDescription.contains("ModelOutput does not contain Int."))
+    } catch let GenerativeModel.GenerationError.decodingFailure(context) {
+      print(context.debugDescription)
+      #expect(context.debugDescription.contains("\"forty\" does not contain Int"))
     } catch {
       Issue.record("Threw an unexpected error: \(error)")
     }

From 2c30bc1f1304f24c5e65b4af378846e7f2831e59 Mon Sep 17 00:00:00 2001
From: Paul Beusterien <paulbeusterien@google.com>
Date: Tue, 25 Nov 2025 12:16:23 -0800
Subject: [PATCH 06/10] remove log

---
 FirebaseAI/Tests/Unit/Types/Generable/GenerableTests.swift | 1 -
 1 file changed, 1 deletion(-)

diff --git a/FirebaseAI/Tests/Unit/Types/Generable/GenerableTests.swift b/FirebaseAI/Tests/Unit/Types/Generable/GenerableTests.swift
index 8c633fbf321..7c83bb55930 100644
--- a/FirebaseAI/Tests/Unit/Types/Generable/GenerableTests.swift
+++ b/FirebaseAI/Tests/Unit/Types/Generable/GenerableTests.swift
@@ -83,7 +83,6 @@ struct GenerableTests {
       _ = try Person(modelOutput)
       Issue.record("Did not throw an error.")
     } catch let GenerativeModel.GenerationError.decodingFailure(context) {
-      print(context.debugDescription)
       #expect(context.debugDescription.contains("\"forty\" does not contain Int"))
     } catch {
       Issue.record("Threw an unexpected error: \(error)")

From 390840a62326fd9882d07f7242178eff735ba40c Mon Sep 17 00:00:00 2001
From: Paul Beusterien <paulbeusterien@google.com>
Date: Tue, 25 Nov 2025 13:23:04 -0800
Subject: [PATCH 07/10] Fix Xcode 16.4 build error

---
 FirebaseAI/Sources/Types/Public/Generable/ModelOutput.swift | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/FirebaseAI/Sources/Types/Public/Generable/ModelOutput.swift b/FirebaseAI/Sources/Types/Public/Generable/ModelOutput.swift
index 153407c8eb6..5c3c54f6517 100644
--- a/FirebaseAI/Sources/Types/Public/Generable/ModelOutput.swift
+++ b/FirebaseAI/Sources/Types/Public/Generable/ModelOutput.swift
@@ -199,7 +199,7 @@ public extension ModelOutput {
     case dataCorrupted(context: Context)
 
     /// The context for a decoding error.
-    public struct Context {
+    public struct Context: Sendable {
       /// A description of the error.
       public let debugDescription: String
     }

From 9a4f2ff04f46cf19232ac7333476e7fd77850fa3 Mon Sep 17 00:00:00 2001
From: Paul Beusterien <paulbeusterien@google.com>
Date: Tue, 25 Nov 2025 14:44:21 -0800
Subject: [PATCH 08/10] cleanup

---
 FirebaseAI/Sources/Types/Public/Generable/ModelOutput.swift | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/FirebaseAI/Sources/Types/Public/Generable/ModelOutput.swift b/FirebaseAI/Sources/Types/Public/Generable/ModelOutput.swift
index 5c3c54f6517..5bedc091028 100644
--- a/FirebaseAI/Sources/Types/Public/Generable/ModelOutput.swift
+++ b/FirebaseAI/Sources/Types/Public/Generable/ModelOutput.swift
@@ -192,9 +192,6 @@ public extension ModelOutput {
     /// A property was accessed on a `ModelOutput` that is not a structure.
     case notAStructure
 
-    /// The type of a property in the `ModelOutput` did not match the expected type.
-    case typeMismatch(context: Context)
-
     /// The data is corrupted or invalid.
     case dataCorrupted(context: Context)
 
@@ -210,8 +207,6 @@ public extension ModelOutput {
         return "Missing property: \(name)"
       case .notAStructure:
         return "Not a structure"
-      case let .typeMismatch(context):
-        return context.debugDescription
       case let .dataCorrupted(context):
         return context.debugDescription
       }

From 609f11a0990d08f7d805dbe46edfb68aadfff99e Mon Sep 17 00:00:00 2001
From: Paul Beusterien <paulbeusterien@google.com>
Date: Tue, 25 Nov 2025 14:52:35 -0800
Subject: [PATCH 09/10] Xcode 16 fixes

---
 .../Unit/Types/Generable/GenerableTests.swift | 231 ++++++++++++------
 1 file changed, 160 insertions(+), 71 deletions(-)

diff --git a/FirebaseAI/Tests/Unit/Types/Generable/GenerableTests.swift b/FirebaseAI/Tests/Unit/Types/Generable/GenerableTests.swift
index 7c83bb55930..be3b3e6c985 100644
--- a/FirebaseAI/Tests/Unit/Types/Generable/GenerableTests.swift
+++ b/FirebaseAI/Tests/Unit/Types/Generable/GenerableTests.swift
@@ -264,56 +264,109 @@ struct GenerableTests {
   }
 }
 
-// An example of the expected output from the `@FirebaseAILogic.Generable` macro.
-@available(iOS 15.0, macOS 12.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
-struct Person: Equatable {
-  let firstName: String
-  let middleName: String?
-  let lastName: String
-  let age: Int
-  let address: Address
-
-  nonisolated static var jsonSchema: FirebaseAILogic.JSONSchema {
-    FirebaseAILogic.JSONSchema(
-      type: Self.self,
-      properties: [
-        FirebaseAILogic.JSONSchema.Property(name: "firstName", type: String.self),
-        FirebaseAILogic.JSONSchema.Property(name: "middleName", type: String?.self),
-        FirebaseAILogic.JSONSchema.Property(name: "lastName", type: String.self),
-        FirebaseAILogic.JSONSchema.Property(name: "age", type: Int.self),
-        FirebaseAILogic.JSONSchema.Property(name: "address", type: Address.self),
-      ]
-    )
+#if compiler(>=6.2)
+  // An example of the expected output from the `@FirebaseAILogic.Generable` macro.
+  @available(iOS 15.0, macOS 12.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
+  struct Person: Equatable {
+    let firstName: String
+    let middleName: String?
+    let lastName: String
+    let age: Int
+    let address: Address
+
+    nonisolated static var jsonSchema: FirebaseAILogic.JSONSchema {
+      FirebaseAILogic.JSONSchema(
+        type: Self.self,
+        properties: [
+          FirebaseAILogic.JSONSchema.Property(name: "firstName", type: String.self),
+          FirebaseAILogic.JSONSchema.Property(name: "middleName", type: String?.self),
+          FirebaseAILogic.JSONSchema.Property(name: "lastName", type: String.self),
+          FirebaseAILogic.JSONSchema.Property(name: "age", type: Int.self),
+          FirebaseAILogic.JSONSchema.Property(name: "address", type: Address.self),
+        ]
+      )
+    }
+
+    nonisolated var modelOutput: FirebaseAILogic.ModelOutput {
+      var properties: [(name: String, value: any FirebaseAILogic.ConvertibleToModelOutput)] = []
+      properties.append(("firstName", firstName))
+      if let middleName {
+        properties.append(("middleName", middleName))
+      }
+      properties.append(("lastName", lastName))
+      properties.append(("age", age))
+      properties.append(("address", address))
+      return ModelOutput(
+        properties: properties,
+        uniquingKeysWith: { _, second in
+          second
+        }
+      )
+    }
   }
 
-  nonisolated var modelOutput: FirebaseAILogic.ModelOutput {
-    var properties: [(name: String, value: any FirebaseAILogic.ConvertibleToModelOutput)] = []
-    properties.append(("firstName", firstName))
-    if let middleName {
-      properties.append(("middleName", middleName))
+  @available(iOS 15.0, macOS 12.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
+  extension Person: nonisolated FirebaseAILogic.Generable {
+    nonisolated init(_ content: FirebaseAILogic.ModelOutput) throws {
+      firstName = try content.value(forProperty: "firstName")
+      middleName = try content.value(forProperty: "middleName")
+      lastName = try content.value(forProperty: "lastName")
+      age = try content.value(forProperty: "age")
+      address = try content.value(forProperty: "address")
+    }
+  }
+#else
+  // An example of the expected output from the `@FirebaseAILogic.Generable` macro.
+  @available(iOS 15.0, macOS 12.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
+  struct Person: Equatable {
+    let firstName: String
+    let middleName: String?
+    let lastName: String
+    let age: Int
+    let address: Address
+
+    static var jsonSchema: FirebaseAILogic.JSONSchema {
+      FirebaseAILogic.JSONSchema(
+        type: Self.self,
+        properties: [
+          FirebaseAILogic.JSONSchema.Property(name: "firstName", type: String.self),
+          FirebaseAILogic.JSONSchema.Property(name: "middleName", type: String?.self),
+          FirebaseAILogic.JSONSchema.Property(name: "lastName", type: String.self),
+          FirebaseAILogic.JSONSchema.Property(name: "age", type: Int.self),
+          FirebaseAILogic.JSONSchema.Property(name: "address", type: Address.self),
+        ]
+      )
     }
-    properties.append(("lastName", lastName))
-    properties.append(("age", age))
-    properties.append(("address", address))
-    return ModelOutput(
-      properties: properties,
-      uniquingKeysWith: { _, second in
-        second
+
+    var modelOutput: FirebaseAILogic.ModelOutput {
+      var properties: [(name: String, value: any FirebaseAILogic.ConvertibleToModelOutput)] = []
+      properties.append(("firstName", firstName))
+      if let middleName {
+        properties.append(("middleName", middleName))
       }
-    )
+      properties.append(("lastName", lastName))
+      properties.append(("age", age))
+      properties.append(("address", address))
+      return ModelOutput(
+        properties: properties,
+        uniquingKeysWith: { _, second in
+          second
+        }
+      )
+    }
   }
-}
 
-@available(iOS 15.0, macOS 12.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
-extension Person: nonisolated FirebaseAILogic.Generable {
-  nonisolated init(_ content: FirebaseAILogic.ModelOutput) throws {
-    firstName = try content.value(forProperty: "firstName")
-    middleName = try content.value(forProperty: "middleName")
-    lastName = try content.value(forProperty: "lastName")
-    age = try content.value(forProperty: "age")
-    address = try content.value(forProperty: "address")
+  @available(iOS 15.0, macOS 12.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
+  extension Person: FirebaseAILogic.Generable {
+    init(_ content: FirebaseAILogic.ModelOutput) throws {
+      firstName = try content.value(forProperty: "firstName")
+      middleName = try content.value(forProperty: "middleName")
+      lastName = try content.value(forProperty: "lastName")
+      age = try content.value(forProperty: "age")
+      address = try content.value(forProperty: "address")
+    }
   }
-}
+#endif
 
 @available(iOS 15.0, macOS 12.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
 struct Address: Equatable {
@@ -322,36 +375,72 @@ struct Address: Equatable {
   let zipCode: String
 }
 
-@available(iOS 15.0, macOS 12.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
-extension Address: nonisolated FirebaseAILogic.Generable {
-  nonisolated static var jsonSchema: FirebaseAILogic.JSONSchema {
-    FirebaseAILogic.JSONSchema(
-      type: Self.self,
-      properties: [
-        FirebaseAILogic.JSONSchema.Property(name: "street", type: String.self),
-        FirebaseAILogic.JSONSchema.Property(name: "city", type: String.self),
-        FirebaseAILogic.JSONSchema.Property(name: "zipCode", type: String.self),
+#if compiler(>=6.2)
+  @available(iOS 15.0, macOS 12.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
+  extension Address: nonisolated FirebaseAILogic.Generable {
+    nonisolated static var jsonSchema: FirebaseAILogic.JSONSchema {
+      FirebaseAILogic.JSONSchema(
+        type: Self.self,
+        properties: [
+          FirebaseAILogic.JSONSchema.Property(name: "street", type: String.self),
+          FirebaseAILogic.JSONSchema.Property(name: "city", type: String.self),
+          FirebaseAILogic.JSONSchema.Property(name: "zipCode", type: String.self),
+        ]
+      )
+    }
+
+    nonisolated var modelOutput: FirebaseAILogic.ModelOutput {
+      let properties: [(name: String, value: any FirebaseAILogic.ConvertibleToModelOutput)] = [
+        ("street", street),
+        ("city", city),
+        ("zipCode", zipCode),
       ]
-    )
-  }
+      return ModelOutput(
+        properties: properties,
+        uniquingKeysWith: { _, second in
+          second
+        }
+      )
+    }
 
-  nonisolated var modelOutput: FirebaseAILogic.ModelOutput {
-    let properties: [(name: String, value: any FirebaseAILogic.ConvertibleToModelOutput)] = [
-      ("street", street),
-      ("city", city),
-      ("zipCode", zipCode),
-    ]
-    return ModelOutput(
-      properties: properties,
-      uniquingKeysWith: { _, second in
-        second
-      }
-    )
+    nonisolated init(_ content: FirebaseAILogic.ModelOutput) throws {
+      street = try content.value(forProperty: "street")
+      city = try content.value(forProperty: "city")
+      zipCode = try content.value(forProperty: "zipCode")
+    }
   }
+#else
+  @available(iOS 15.0, macOS 12.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
+  extension Address: FirebaseAILogic.Generable {
+    static var jsonSchema: FirebaseAILogic.JSONSchema {
+      FirebaseAILogic.JSONSchema(
+        type: Self.self,
+        properties: [
+          FirebaseAILogic.JSONSchema.Property(name: "street", type: String.self),
+          FirebaseAILogic.JSONSchema.Property(name: "city", type: String.self),
+          FirebaseAILogic.JSONSchema.Property(name: "zipCode", type: String.self),
+        ]
+      )
+    }
 
-  nonisolated init(_ content: FirebaseAILogic.ModelOutput) throws {
-    street = try content.value(forProperty: "street")
-    city = try content.value(forProperty: "city")
-    zipCode = try content.value(forProperty: "zipCode")
+    var modelOutput: FirebaseAILogic.ModelOutput {
+      let properties: [(name: String, value: any FirebaseAILogic.ConvertibleToModelOutput)] = [
+        ("street", street),
+        ("city", city),
+        ("zipCode", zipCode),
+      ]
+      return ModelOutput(
+        properties: properties,
+        uniquingKeysWith: { _, second in
+          second
+        }
+      )
+    }
+
+    init(_ content: FirebaseAILogic.ModelOutput) throws {
+      street = try content.value(forProperty: "street")
+      city = try content.value(forProperty: "city")
+      zipCode = try content.value(forProperty: "zipCode")
+    }
   }
-}
+#endif

From 0db7eda804ce2123187e7d0bfb52bd96cb5d16a2 Mon Sep 17 00:00:00 2001
From: Paul Beusterien <paulbeusterien@google.com>
Date: Tue, 25 Nov 2025 15:57:35 -0800
Subject: [PATCH 10/10] Updates after rebase

---
 FirebaseAI/Sources/Types/Public/Generable/ModelOutput.swift | 5 -----
 FirebaseAI/Tests/Unit/Types/Generable/GenerableTests.swift  | 4 ++--
 2 files changed, 2 insertions(+), 7 deletions(-)

diff --git a/FirebaseAI/Sources/Types/Public/Generable/ModelOutput.swift b/FirebaseAI/Sources/Types/Public/Generable/ModelOutput.swift
index 5bedc091028..da3c09cc452 100644
--- a/FirebaseAI/Sources/Types/Public/Generable/ModelOutput.swift
+++ b/FirebaseAI/Sources/Types/Public/Generable/ModelOutput.swift
@@ -192,9 +192,6 @@ public extension ModelOutput {
     /// A property was accessed on a `ModelOutput` that is not a structure.
     case notAStructure
 
-    /// The data is corrupted or invalid.
-    case dataCorrupted(context: Context)
-
     /// The context for a decoding error.
     public struct Context: Sendable {
       /// A description of the error.
@@ -207,8 +204,6 @@ public extension ModelOutput {
         return "Missing property: \(name)"
       case .notAStructure:
         return "Not a structure"
-      case let .dataCorrupted(context):
-        return context.debugDescription
       }
     }
   }
diff --git a/FirebaseAI/Tests/Unit/Types/Generable/GenerableTests.swift b/FirebaseAI/Tests/Unit/Types/Generable/GenerableTests.swift
index be3b3e6c985..a4f863b294c 100644
--- a/FirebaseAI/Tests/Unit/Types/Generable/GenerableTests.swift
+++ b/FirebaseAI/Tests/Unit/Types/Generable/GenerableTests.swift
@@ -100,8 +100,8 @@ struct GenerableTests {
     do {
       _ = try Person(modelOutput)
       Issue.record("Did not throw an error.")
-    } catch let ModelOutput.DecodingError.dataCorrupted(context) {
-      #expect(context.debugDescription.contains("ModelOutput cannot be represented as Int."))
+    } catch let GenerativeModel.GenerationError.decodingFailure(context) {
+      #expect(context.debugDescription.contains("40.5 does not contain Int."))
     } catch {
       Issue.record("Threw an unexpected error: \(error)")
     }