diff --git a/FirebaseAI/Sources/Types/Public/Generable/ModelOutput.swift b/FirebaseAI/Sources/Types/Public/Generable/ModelOutput.swift
index 36d3626dde5..da3c09cc452 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
@@ -146,7 +150,7 @@ 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 +158,10 @@ 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 +172,7 @@ 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
@@ -183,11 +184,35 @@ 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, CustomDebugStringConvertible {
+    /// 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 context for a decoding error.
+    public struct Context: Sendable {
+      /// 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"
+      }
+    }
+  }
+
   /// 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
 
@@ -212,5 +237,27 @@ 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 365403709ea..a4f863b294c 100644
--- a/FirebaseAI/Tests/Unit/Types/Generable/GenerableTests.swift
+++ b/FirebaseAI/Tests/Unit/Types/Generable/GenerableTests.swift
@@ -12,14 +12,19 @@
 // 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)]
+      [("firstName", "John"), ("lastName", "Doe"), ("age", 40), ("address", addressModelOutput)]
     let modelOutput = ModelOutput(
       properties: properties, uniquingKeysWith: { _, second in second }
     )
@@ -29,11 +34,142 @@ 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 initializeGenerableWithMissingProperty() throws {
+    let properties: [(String, any ConvertibleToModelOutput)] =
+      [("firstName", "John"), ("age", 40)]
+    let modelOutput = ModelOutput(
+      properties: properties, uniquingKeysWith: { _, second in second }
+    )
+
+    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)")
+    }
+  }
+
+  @Test
+  func initializeGenerableFromNonStructure() throws {
+    let modelOutput = ModelOutput("not a structure")
+
+    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)")
+    }
+  }
+
+  @Test
+  func initializeGenerableWithTypeMismatch() throws {
+    let properties: [(String, any ConvertibleToModelOutput)] =
+      [("firstName", "John"), ("lastName", "Doe"), ("age", "forty")]
+    let modelOutput = ModelOutput(
+      properties: properties, uniquingKeysWith: { _, second in second }
+    )
+
+    do {
+      _ = try Person(modelOutput)
+      Issue.record("Did not throw an error.")
+    } catch let GenerativeModel.GenerationError.decodingFailure(context) {
+      #expect(context.debugDescription.contains("\"forty\" does not contain Int"))
+    } catch {
+      Issue.record("Threw an unexpected error: \(error)")
+    }
+  }
+
+  @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 GenerativeModel.GenerationError.decodingFailure(context) {
+      #expect(context.debugDescription.contains("40.5 does not contain Int."))
+    } catch {
+      Issue.record("Threw an unexpected error: \(error)")
+    }
+  }
+
+  @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),
+        ("address", addressModelOutput),
+        ("country", "USA"),
+      ]
+    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 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
 
@@ -69,56 +205,106 @@ 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"])
   }
-}
 
-// 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
-
-  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),
-      ]
+  @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
     )
-  }
 
-  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)
-    return ModelOutput(
-      properties: properties,
-      uniquingKeysWith: { _, second in
-        second
-      }
-    )
-    func addProperty(name: String, value: some FirebaseAILogic.Generable) {
-      properties.append((name, value))
+    let modelOutput = person.modelOutput
+
+    guard case let .structure(properties, orderedKeys) = modelOutput.kind else {
+      Issue.record("Model output is not a structure.")
+      return
     }
-    func addProperty(name: String, value: (some FirebaseAILogic.Generable)?) {
-      if let value {
-        properties.append((name, value))
-      }
+
+    #expect(properties["middleName"] == nil)
+    #expect(orderedKeys == ["firstName", "lastName", "age", "address"])
+  }
+
+  @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)
   }
 }
 
 #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
+        }
+      )
+    }
+  }
+
   @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 {
@@ -126,16 +312,135 @@ struct Person: Equatable {
       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),
+        ]
+      )
+    }
+
+    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: FirebaseAILogic.Generable {
-    nonisolated init(_ content: FirebaseAILogic.ModelOutput) throws {
+    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 {
+  let street: String
+  let city: String
+  let zipCode: String
+}
+
+#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 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),
+        ]
+      )
+    }
+
+    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