diff --git a/FirebaseVertexAI/CHANGELOG.md b/FirebaseVertexAI/CHANGELOG.md
index fc54c727370..25f3f3181e0 100644
--- a/FirebaseVertexAI/CHANGELOG.md
+++ b/FirebaseVertexAI/CHANGELOG.md
@@ -1,3 +1,37 @@
+# 11.4.0
+- [changed] **Breaking Change**: The `HarmCategory` enum is no longer nested
+  inside the `SafetySetting` struct and the `unspecified` case has been
+  removed. (#13686)
+- [changed] **Breaking Change**: The `BlockThreshold` enum in `SafetySetting`
+  has been renamed to `HarmBlockThreshold`. (#13696)
+- [changed] **Breaking Change**: The `unspecified` case has been removed from
+  the `FinishReason`, `BlockReason` and `HarmProbability` enums; this scenario
+  is now handled by the existing `unknown` case. (#13699)
+- [changed] **Breaking Change**: The `data` case in the `Part` enum has been
+  renamed to `inlineData`; no functionality changes. (#13700)
+- [changed] **Breaking Change**: The property `citationSources` of
+  `CitationMetadata` has been renamed to `citations`. (#13702)
+- [changed] **Breaking Change**: The constructor for `Schema` is now deprecated;
+  use the new static methods `Schema.string(...)`, `Schema.object(...)`, etc.,
+  instead. (#13616)
+- [changed] **Breaking Change**: The constructor for `FunctionDeclaration` now
+  accepts an array of *optional* parameters instead of a list of *required*
+  parameters; if a parameter is not listed as optional it is assumed to be
+  required. (#13616)
+- [changed] **Breaking Change**: `CountTokensResponse.totalBillableCharacters`
+  is now optional (`Int?`); it may be `null` in cases such as when a
+  `GenerateContentRequest` contains only images or other non-text content.
+  (#13721)
+- [changed] **Breaking Change**: The `ImageConversionError` enum is no longer
+  public; image conversion errors are still reported as
+  `GenerateContentError.promptImageContentError`. (#13735)
+- [changed] **Breaking Change**: The `CountTokensError` enum has been removed;
+  errors occurring in `GenerativeModel.countTokens(...)` are now thrown directly
+  instead of being wrapped in a `CountTokensError.internalError`. (#13736)
+- [changed] The default request timeout is now 180 seconds instead of the
+  platform-default value of 60 seconds for a `URLRequest`; this timeout may
+  still be customized in `RequestOptions`. (#13722)
+
 # 11.3.0
 - [added] Added `Decodable` conformance for `FunctionResponse`. (#13606)
 - [changed] **Breaking Change**: Reverted refactor of `GenerativeModel` and
diff --git a/FirebaseVertexAI/Sample/ChatSample/Views/ErrorDetailsView.swift b/FirebaseVertexAI/Sample/ChatSample/Views/ErrorDetailsView.swift
index dc5ce8f9561..b8febfe0e40 100644
--- a/FirebaseVertexAI/Sample/ChatSample/Views/ErrorDetailsView.swift
+++ b/FirebaseVertexAI/Sample/ChatSample/Views/ErrorDetailsView.swift
@@ -16,7 +16,7 @@ import FirebaseVertexAI
 import MarkdownUI
 import SwiftUI
 
-extension SafetySetting.HarmCategory: CustomStringConvertible {
+extension HarmCategory: CustomStringConvertible {
   public var description: String {
     switch self {
     case .dangerousContent: "Dangerous content"
@@ -24,7 +24,6 @@ extension SafetySetting.HarmCategory: CustomStringConvertible {
     case .hateSpeech: "Hate speech"
     case .sexuallyExplicit: "Sexually explicit"
     case .unknown: "Unknown"
-    case .unspecified: "Unspecified"
     }
   }
 }
@@ -37,7 +36,6 @@ extension SafetyRating.HarmProbability: CustomStringConvertible {
     case .medium: "Medium"
     case .negligible: "Negligible"
     case .unknown: "Unknown"
-    case .unspecified: "Unspecified"
     }
   }
 }
diff --git a/FirebaseVertexAI/Sample/FunctionCallingSample/ViewModels/FunctionCallingViewModel.swift b/FirebaseVertexAI/Sample/FunctionCallingSample/ViewModels/FunctionCallingViewModel.swift
index ac2ea5a1fcc..110cab9ce27 100644
--- a/FirebaseVertexAI/Sample/FunctionCallingSample/ViewModels/FunctionCallingViewModel.swift
+++ b/FirebaseVertexAI/Sample/FunctionCallingSample/ViewModels/FunctionCallingViewModel.swift
@@ -45,20 +45,15 @@ class FunctionCallingViewModel: ObservableObject {
           name: "get_exchange_rate",
           description: "Get the exchange rate for currencies between countries",
           parameters: [
-            "currency_from": Schema(
-              type: .string,
-              format: "enum",
-              description: "The currency to convert from in ISO 4217 format",
-              enumValues: ["USD", "EUR", "JPY", "GBP", "AUD", "CAD"]
+            "currency_from": .enumeration(
+              values: ["USD", "EUR", "JPY", "GBP", "AUD", "CAD"],
+              description: "The currency to convert from in ISO 4217 format"
             ),
-            "currency_to": Schema(
-              type: .string,
-              format: "enum",
-              description: "The currency to convert to in ISO 4217 format",
-              enumValues: ["USD", "EUR", "JPY", "GBP", "AUD", "CAD"]
+            "currency_to": .enumeration(
+              values: ["USD", "EUR", "JPY", "GBP", "AUD", "CAD"],
+              description: "The currency to convert to in ISO 4217 format"
             ),
-          ],
-          requiredParameters: ["currency_from", "currency_to"]
+          ]
         ),
       ])]
     )
@@ -156,7 +151,7 @@ class FunctionCallingViewModel: ObservableObject {
       case let .functionCall(functionCall):
         messages.insert(functionCall.chatMessage(), at: messages.count - 1)
         functionCalls.append(functionCall)
-      case .data, .fileData, .functionResponse:
+      case .inlineData, .fileData, .functionResponse:
         fatalError("Unsupported response content.")
       }
     }
diff --git a/FirebaseVertexAI/Sources/Chat.swift b/FirebaseVertexAI/Sources/Chat.swift
index ff7a8aa9a09..10df040ab30 100644
--- a/FirebaseVertexAI/Sources/Chat.swift
+++ b/FirebaseVertexAI/Sources/Chat.swift
@@ -155,7 +155,7 @@ public class Chat {
         case let .text(str):
           combinedText += str
 
-        case .data, .fileData, .functionCall, .functionResponse:
+        case .inlineData, .fileData, .functionCall, .functionResponse:
           // Don't combine it, just add to the content. If there's any text pending, add that as
           // a part.
           if !combinedText.isEmpty {
diff --git a/FirebaseVertexAI/Sources/Constants.swift b/FirebaseVertexAI/Sources/Constants.swift
index 8f1768d7082..e3f2d45d6df 100644
--- a/FirebaseVertexAI/Sources/Constants.swift
+++ b/FirebaseVertexAI/Sources/Constants.swift
@@ -21,5 +21,8 @@ import Foundation
 /// Constants associated with the Vertex AI for Firebase SDK.
 enum Constants {
   /// The Vertex AI backend endpoint URL.
+  ///
+  /// TODO(andrewheard): Update to "https://firebasevertexai.googleapis.com" after the Vertex AI in
+  /// Firebase API launch.
   static let baseURL = "https://firebaseml.googleapis.com"
 }
diff --git a/FirebaseVertexAI/Sources/CountTokensRequest.swift b/FirebaseVertexAI/Sources/CountTokensRequest.swift
index feddf9b2a05..6b052da19e6 100644
--- a/FirebaseVertexAI/Sources/CountTokensRequest.swift
+++ b/FirebaseVertexAI/Sources/CountTokensRequest.swift
@@ -40,7 +40,7 @@ public struct CountTokensResponse {
   ///
   /// > Important: This does not include billable image, video or other non-text input. See
   /// [Vertex AI pricing](https://cloud.google.com/vertex-ai/generative-ai/pricing) for details.
-  public let totalBillableCharacters: Int
+  public let totalBillableCharacters: Int?
 }
 
 // MARK: - Codable Conformances
@@ -53,18 +53,4 @@ extension CountTokensRequest: Encodable {
 }
 
 @available(iOS 15.0, macOS 11.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
-extension CountTokensResponse: Decodable {
-  enum CodingKeys: CodingKey {
-    case totalTokens
-    case totalBillableCharacters
-  }
-
-  public init(from decoder: any Decoder) throws {
-    let container = try decoder.container(keyedBy: CodingKeys.self)
-    totalTokens = try container.decode(Int.self, forKey: .totalTokens)
-    totalBillableCharacters = try container.decodeIfPresent(
-      Int.self,
-      forKey: .totalBillableCharacters
-    ) ?? 0
-  }
-}
+extension CountTokensResponse: Decodable {}
diff --git a/FirebaseVertexAI/Sources/Errors.swift b/FirebaseVertexAI/Sources/Errors.swift
index 17a4dd9e201..57fbe826580 100644
--- a/FirebaseVertexAI/Sources/Errors.swift
+++ b/FirebaseVertexAI/Sources/Errors.swift
@@ -31,9 +31,14 @@ struct RPCError: Error {
     self.details = details
   }
 
+  // TODO(andrewheard): Remove this method after the Vertex AI in Firebase API launch.
   func isFirebaseMLServiceDisabledError() -> Bool {
     return details.contains { $0.isFirebaseMLServiceDisabledErrorDetails() }
   }
+
+  func isVertexAIInFirebaseServiceDisabledError() -> Bool {
+    return details.contains { $0.isVertexAIInFirebaseServiceDisabledErrorDetails() }
+  }
 }
 
 extension RPCError: Decodable {
@@ -86,17 +91,26 @@ struct ErrorDetails {
     return type == ErrorDetails.errorInfoType
   }
 
+  func isServiceDisabledError() -> Bool {
+    return isErrorInfo() && reason == "SERVICE_DISABLED" && domain == "googleapis.com"
+  }
+
+  // TODO(andrewheard): Remove this method after the Vertex AI in Firebase API launch.
   func isFirebaseMLServiceDisabledErrorDetails() -> Bool {
-    guard isErrorInfo() else {
+    guard isServiceDisabledError() else {
       return false
     }
-    guard reason == "SERVICE_DISABLED" else {
+    guard let metadata, metadata["service"] == "firebaseml.googleapis.com" else {
       return false
     }
-    guard domain == "googleapis.com" else {
+    return true
+  }
+
+  func isVertexAIInFirebaseServiceDisabledErrorDetails() -> Bool {
+    guard isServiceDisabledError() else {
       return false
     }
-    guard let metadata, metadata["service"] == "firebaseml.googleapis.com" else {
+    guard let metadata, metadata["service"] == "firebasevertexai.googleapis.com" else {
       return false
     }
     return true
diff --git a/FirebaseVertexAI/Sources/FunctionCalling.swift b/FirebaseVertexAI/Sources/FunctionCalling.swift
index 3c88279c6df..4641a6f400f 100644
--- a/FirebaseVertexAI/Sources/FunctionCalling.swift
+++ b/FirebaseVertexAI/Sources/FunctionCalling.swift
@@ -43,17 +43,15 @@ public struct FunctionDeclaration {
   ///   - name: The name of the function; must be a-z, A-Z, 0-9, or contain underscores and dashes,
   ///   with a maximum length of 63.
   ///   - description: A brief description of the function.
-  ///   - parameters: Describes the parameters to this function; the keys are parameter names and
-  ///   the values are ``Schema`` objects describing them.
-  ///   - requiredParameters: A list of required parameters by name.
-  public init(name: String, description: String, parameters: [String: Schema]?,
-              requiredParameters: [String]? = nil) {
+  ///   - parameters: Describes the parameters to this function.
+  public init(name: String, description: String, parameters: [String: Schema],
+              optionalParameters: [String] = []) {
     self.name = name
     self.description = description
-    self.parameters = Schema(
-      type: .object,
+    self.parameters = Schema.object(
       properties: parameters,
-      requiredProperties: requiredParameters
+      optionalProperties: optionalParameters,
+      nullable: false
     )
   }
 }
diff --git a/FirebaseVertexAI/Sources/GenerateContentError.swift b/FirebaseVertexAI/Sources/GenerateContentError.swift
index 5428223853f..b5b52d0acd5 100644
--- a/FirebaseVertexAI/Sources/GenerateContentError.swift
+++ b/FirebaseVertexAI/Sources/GenerateContentError.swift
@@ -17,12 +17,12 @@ import Foundation
 /// Errors that occur when generating content from a model.
 @available(iOS 15.0, macOS 11.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
 public enum GenerateContentError: Error {
-  /// An error occurred when constructing the prompt. Examine the related error for details.
-  case promptImageContentError(underlying: ImageConversionError)
-
   /// An internal error occurred. See the underlying error for more context.
   case internalError(underlying: Error)
 
+  /// An error occurred when constructing the prompt. Examine the related error for details.
+  case promptImageContentError(underlying: Error)
+
   /// A prompt was blocked. See the response's `promptFeedback.blockReason` for more information.
   case promptBlocked(response: GenerateContentResponse)
 
diff --git a/FirebaseVertexAI/Sources/GenerateContentResponse.swift b/FirebaseVertexAI/Sources/GenerateContentResponse.swift
index c9f085971ea..66dd83aec16 100644
--- a/FirebaseVertexAI/Sources/GenerateContentResponse.swift
+++ b/FirebaseVertexAI/Sources/GenerateContentResponse.swift
@@ -42,8 +42,10 @@ public struct GenerateContentResponse: Sendable {
   /// The response's content as text, if it exists.
   public var text: String? {
     guard let candidate = candidates.first else {
-      Logging.default
-        .error("[FirebaseVertexAI] Could not get text from a response that had no candidates.")
+      VertexLog.error(
+        code: .generateContentResponseNoCandidates,
+        "Could not get text from a response that had no candidates."
+      )
       return nil
     }
     let textValues: [String] = candidate.content.parts.compactMap { part in
@@ -53,8 +55,10 @@ public struct GenerateContentResponse: Sendable {
       return text
     }
     guard textValues.count > 0 else {
-      Logging.default
-        .error("[FirebaseVertexAI] Could not get a text part from the first candidate.")
+      VertexLog.error(
+        code: .generateContentResponseNoText,
+        "Could not get a text part from the first candidate."
+      )
       return nil
     }
     return textValues.joined(separator: " ")
@@ -113,7 +117,7 @@ public struct CandidateResponse: Sendable {
 @available(iOS 15.0, macOS 11.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
 public struct CitationMetadata: Sendable {
   /// A list of individual cited sources and the parts of the content to which they apply.
-  public let citationSources: [Citation]
+  public let citations: [Citation]
 }
 
 /// A struct describing a source attribution.
@@ -138,10 +142,9 @@ public struct Citation: Sendable {
 /// A value enumerating possible reasons for a model to terminate a content generation request.
 @available(iOS 15.0, macOS 11.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
 public enum FinishReason: String, Sendable {
+  /// The finish reason is unknown.
   case unknown = "FINISH_REASON_UNKNOWN"
 
-  case unspecified = "FINISH_REASON_UNSPECIFIED"
-
   /// Natural stop point of the model or provided stop sequence.
   case stop = "STOP"
 
@@ -168,9 +171,6 @@ public struct PromptFeedback: Sendable {
     /// The block reason is unknown.
     case unknown = "UNKNOWN"
 
-    /// The block reason was not specified in the server response.
-    case unspecified = "BLOCK_REASON_UNSPECIFIED"
-
     /// The prompt was blocked because it was deemed unsafe.
     case safety = "SAFETY"
 
@@ -294,11 +294,7 @@ extension CandidateResponse: Decodable {
 }
 
 @available(iOS 15.0, macOS 11.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
-extension CitationMetadata: Decodable {
-  enum CodingKeys: String, CodingKey {
-    case citationSources = "citations"
-  }
-}
+extension CitationMetadata: Decodable {}
 
 @available(iOS 15.0, macOS 11.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
 extension Citation: Decodable {
@@ -338,8 +334,10 @@ extension FinishReason: Decodable {
   public init(from decoder: Decoder) throws {
     let value = try decoder.singleValueContainer().decode(String.self)
     guard let decodedFinishReason = FinishReason(rawValue: value) else {
-      Logging.default
-        .error("[FirebaseVertexAI] Unrecognized FinishReason with value \"\(value)\".")
+      VertexLog.error(
+        code: .generateContentResponseUnrecognizedFinishReason,
+        "Unrecognized FinishReason with value \"\(value)\"."
+      )
       self = .unknown
       return
     }
@@ -353,8 +351,10 @@ extension PromptFeedback.BlockReason: Decodable {
   public init(from decoder: Decoder) throws {
     let value = try decoder.singleValueContainer().decode(String.self)
     guard let decodedBlockReason = PromptFeedback.BlockReason(rawValue: value) else {
-      Logging.default
-        .error("[FirebaseVertexAI] Unrecognized BlockReason with value \"\(value)\".")
+      VertexLog.error(
+        code: .generateContentResponseUnrecognizedBlockReason,
+        "Unrecognized BlockReason with value \"\(value)\"."
+      )
       self = .unknown
       return
     }
diff --git a/FirebaseVertexAI/Sources/GenerativeAIRequest.swift b/FirebaseVertexAI/Sources/GenerativeAIRequest.swift
index 08b178d5808..08ac22eaa5f 100644
--- a/FirebaseVertexAI/Sources/GenerativeAIRequest.swift
+++ b/FirebaseVertexAI/Sources/GenerativeAIRequest.swift
@@ -28,17 +28,18 @@ protocol GenerativeAIRequest: Encodable {
 public struct RequestOptions {
   /// The request’s timeout interval in seconds; if not specified uses the default value for a
   /// `URLRequest`.
-  let timeout: TimeInterval?
+  let timeout: TimeInterval
 
   /// The API version to use in requests to the backend.
+  ///
+  /// TODO(andrewheard): Update to "v1beta" after the Vertex AI in Firebase API launch.
   let apiVersion = "v2beta"
 
   /// Initializes a request options object.
   ///
   /// - Parameters:
-  ///   - timeout The request’s timeout interval in seconds; if not specified uses the default value
-  ///   for a `URLRequest`.
-  public init(timeout: TimeInterval? = nil) {
+  ///   - timeout The request’s timeout interval in seconds; defaults to 180 seconds.
+  public init(timeout: TimeInterval = 180.0) {
     self.timeout = timeout
   }
 }
diff --git a/FirebaseVertexAI/Sources/GenerativeAIService.swift b/FirebaseVertexAI/Sources/GenerativeAIService.swift
index 3ebbf69f102..0e2e39169ea 100644
--- a/FirebaseVertexAI/Sources/GenerativeAIService.swift
+++ b/FirebaseVertexAI/Sources/GenerativeAIService.swift
@@ -16,6 +16,7 @@ import FirebaseAppCheckInterop
 import FirebaseAuthInterop
 import FirebaseCore
 import Foundation
+import os.log
 
 @available(iOS 15.0, macOS 11.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
 struct GenerativeAIService {
@@ -60,9 +61,15 @@ struct GenerativeAIService {
 
     // Verify the status code is 200
     guard response.statusCode == 200 else {
-      Logging.network.error("[FirebaseVertexAI] The server responded with an error: \(response)")
+      VertexLog.error(
+        code: .loadRequestResponseError,
+        "The server responded with an error: \(response)"
+      )
       if let responseString = String(data: data, encoding: .utf8) {
-        Logging.default.error("[FirebaseVertexAI] Response payload: \(responseString)")
+        VertexLog.error(
+          code: .loadRequestResponseErrorPayload,
+          "Response payload: \(responseString)"
+        )
       }
 
       throw parseError(responseData: data)
@@ -108,14 +115,19 @@ struct GenerativeAIService {
 
         // Verify the status code is 200
         guard response.statusCode == 200 else {
-          Logging.network
-            .error("[FirebaseVertexAI] The server responded with an error: \(response)")
+          VertexLog.error(
+            code: .loadRequestStreamResponseError,
+            "The server responded with an error: \(response)"
+          )
           var responseBody = ""
           for try await line in stream.lines {
             responseBody += line + "\n"
           }
 
-          Logging.default.error("[FirebaseVertexAI] Response payload: \(responseBody)")
+          VertexLog.error(
+            code: .loadRequestStreamResponseErrorPayload,
+            "Response payload: \(responseBody)"
+          )
           continuation.finish(throwing: parseError(responseBody: responseBody))
 
           return
@@ -127,7 +139,7 @@ struct GenerativeAIService {
         let decoder = JSONDecoder()
         decoder.keyDecodingStrategy = .convertFromSnakeCase
         for try await line in stream.lines {
-          Logging.network.debug("[FirebaseVertexAI] Stream response: \(line)")
+          VertexLog.debug(code: .loadRequestStreamResponseLine, "Stream response: \(line)")
 
           if line.hasPrefix("data:") {
             // We can assume 5 characters since it's utf-8 encoded, removing `data:`.
@@ -179,8 +191,10 @@ struct GenerativeAIService {
       let tokenResult = await appCheck.getToken(forcingRefresh: false)
       urlRequest.setValue(tokenResult.token, forHTTPHeaderField: "X-Firebase-AppCheck")
       if let error = tokenResult.error {
-        Logging.default
-          .debug("[FirebaseVertexAI] Failed to fetch AppCheck token. Error: \(error)")
+        VertexLog.error(
+          code: .appCheckTokenFetchFailed,
+          "Failed to fetch AppCheck token. Error: \(error)"
+        )
       }
     }
 
@@ -191,10 +205,7 @@ struct GenerativeAIService {
     let encoder = JSONEncoder()
     encoder.keyEncodingStrategy = .convertToSnakeCase
     urlRequest.httpBody = try encoder.encode(request)
-
-    if let timeoutInterval = request.options.timeout {
-      urlRequest.timeoutInterval = timeoutInterval
-    }
+    urlRequest.timeoutInterval = request.options.timeout
 
     return urlRequest
   }
@@ -202,10 +213,10 @@ struct GenerativeAIService {
   private func httpResponse(urlResponse: URLResponse) throws -> HTTPURLResponse {
     // Verify the status code is 200
     guard let response = urlResponse as? HTTPURLResponse else {
-      Logging.default
-        .error(
-          "[FirebaseVertexAI] Response wasn't an HTTP response, internal error \(urlResponse)"
-        )
+      VertexLog.error(
+        code: .generativeAIServiceNonHTTPResponse,
+        "Response wasn't an HTTP response, internal error \(urlResponse)"
+      )
       throw NSError(
         domain: "com.google.generative-ai",
         code: -1,
@@ -252,8 +263,9 @@ struct GenerativeAIService {
   // Log specific RPC errors that cannot be mitigated or handled by user code.
   // These errors do not produce specific GenerateContentError or CountTokensError cases.
   private func logRPCError(_ error: RPCError) {
+    // TODO(andrewheard): Remove this check after the Vertex AI in Firebase API launch.
     if error.isFirebaseMLServiceDisabledError() {
-      Logging.default.error("""
+      VertexLog.error(code: .vertexAIInFirebaseAPIDisabled, """
       The Vertex AI for Firebase SDK requires the Firebase ML API `firebaseml.googleapis.com` to \
       be enabled for your project. Get started in the Firebase Console \
       (https://console.firebase.google.com/project/\(projectID)/genai/vertex) or verify that the \
@@ -262,6 +274,15 @@ struct GenerativeAIService {
       \(projectID)).
       """)
     }
+
+    if error.isVertexAIInFirebaseServiceDisabledError() {
+      VertexLog.error(code: .vertexAIInFirebaseAPIDisabled, """
+      The Vertex AI for Firebase SDK requires the Firebase Vertex AI API \
+      `firebasevertexai.googleapis.com` to be enabled for your project. Get started by visiting \
+      the Firebase Console at: \
+      https://console.firebase.google.com/project/\(projectID)/genai/vertex
+      """)
+    }
   }
 
   private func parseResponse<T: Decodable>(_ type: T.Type, from data: Data) throws -> T {
@@ -269,9 +290,12 @@ struct GenerativeAIService {
       return try JSONDecoder().decode(type, from: data)
     } catch {
       if let json = String(data: data, encoding: .utf8) {
-        Logging.network.error("[FirebaseVertexAI] JSON response: \(json)")
+        VertexLog.error(code: .loadRequestParseResponseFailedJSON, "JSON response: \(json)")
       }
-      Logging.default.error("[FirebaseVertexAI] Error decoding server JSON: \(error)")
+      VertexLog.error(
+        code: .loadRequestParseResponseFailedJSONError,
+        "Error decoding server JSON: \(error)"
+      )
       throw error
     }
   }
@@ -297,9 +321,12 @@ struct GenerativeAIService {
     }
 
     private func printCURLCommand(from request: URLRequest) {
+      guard VertexLog.additionalLoggingEnabled() else {
+        return
+      }
       let command = cURLCommand(from: request)
-      Logging.verbose.debug("""
-      [FirebaseVertexAI] Creating request with the equivalent cURL command:
+      os_log(.debug, log: VertexLog.logObject, """
+      \(VertexLog.service) Creating request with the equivalent cURL command:
       ----- cURL command -----
       \(command, privacy: .private)
       ------------------------
diff --git a/FirebaseVertexAI/Sources/GenerativeModel.swift b/FirebaseVertexAI/Sources/GenerativeModel.swift
index 28d3ca4ba88..a5a8933e435 100644
--- a/FirebaseVertexAI/Sources/GenerativeModel.swift
+++ b/FirebaseVertexAI/Sources/GenerativeModel.swift
@@ -85,23 +85,15 @@ public final class GenerativeModel {
     self.systemInstruction = systemInstruction
     self.requestOptions = requestOptions
 
-    if Logging.additionalLoggingEnabled() {
-      if ProcessInfo.processInfo.arguments.contains(Logging.migrationEnableArgumentKey) {
-        Logging.verbose.debug("""
-        [FirebaseVertexAI] Verbose logging enabled with the \
-        \(Logging.migrationEnableArgumentKey, privacy: .public) launch argument; please migrate to \
-        the \(Logging.enableArgumentKey, privacy: .public) argument to ensure future compatibility.
-        """)
-      } else {
-        Logging.verbose.debug("[FirebaseVertexAI] Verbose logging enabled.")
-      }
+    if VertexLog.additionalLoggingEnabled() {
+      VertexLog.debug(code: .verboseLoggingEnabled, "Verbose logging enabled.")
     } else {
-      Logging.default.info("""
+      VertexLog.info(code: .verboseLoggingDisabled, """
       [FirebaseVertexAI] To enable additional logging, add \
-      `\(Logging.enableArgumentKey, privacy: .public)` as a launch argument in Xcode.
+      `\(VertexLog.enableArgumentKey)` as a launch argument in Xcode.
       """)
     }
-    Logging.default.debug("[FirebaseVertexAI] Model \(name, privacy: .public) initialized.")
+    VertexLog.debug(code: .generativeModelInitialized, "Model \(name) initialized.")
   }
 
   /// Generates content from String and/or image inputs, given to the model as a prompt, that are
@@ -277,16 +269,12 @@ public final class GenerativeModel {
   /// invalid.
   public func countTokens(_ content: @autoclosure () throws -> [ModelContent]) async throws
     -> CountTokensResponse {
-    do {
-      let countTokensRequest = try CountTokensRequest(
-        model: modelResourceName,
-        contents: content(),
-        options: requestOptions
-      )
-      return try await generativeAIService.loadRequest(request: countTokensRequest)
-    } catch {
-      throw CountTokensError.internalError(underlying: error)
-    }
+    let countTokensRequest = try CountTokensRequest(
+      model: modelResourceName,
+      contents: content(),
+      options: requestOptions
+    )
+    return try await generativeAIService.loadRequest(request: countTokensRequest)
   }
 
   /// Returns a `GenerateContentError` (for public consumption) from an internal error.
@@ -299,9 +287,3 @@ public final class GenerativeModel {
     return GenerateContentError.internalError(underlying: error)
   }
 }
-
-/// An error thrown in `GenerativeModel.countTokens(_:)`.
-@available(iOS 15.0, macOS 11.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
-public enum CountTokensError: Error {
-  case internalError(underlying: Error)
-}
diff --git a/FirebaseVertexAI/Sources/Logging.swift b/FirebaseVertexAI/Sources/Logging.swift
deleted file mode 100644
index 5806ac2368a..00000000000
--- a/FirebaseVertexAI/Sources/Logging.swift
+++ /dev/null
@@ -1,71 +0,0 @@
-// Copyright 2023 Google LLC
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//      http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-import Foundation
-import OSLog
-
-@available(iOS 15.0, macOS 11.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
-struct Logging {
-  /// Subsystem that should be used for all Loggers.
-  static let subsystem = "com.google.firebase.vertex-ai"
-
-  /// Default category used for most loggers, unless specialized.
-  static let defaultCategory = ""
-
-  /// The argument required to enable additional logging.
-  static let enableArgumentKey = "-FIRDebugEnabled"
-
-  /// The argument required to enable additional logging in the Google AI SDK; used for migration.
-  ///
-  /// To facilitate migration between the SDKs, this launch argument is also accepted to enable
-  /// additional logging at this time, though it is expected to be removed in the future.
-  static let migrationEnableArgumentKey = "-GoogleGenerativeAIDebugLogEnabled"
-
-  // No initializer available.
-  @available(*, unavailable)
-  private init() {}
-
-  /// The default logger that is visible for all users. Note: we shouldn't be using anything lower
-  /// than `.notice`.
-  static let `default` = Logger(subsystem: subsystem, category: defaultCategory)
-
-  /// A non default
-  static let network: Logger = {
-    if additionalLoggingEnabled() {
-      return Logger(subsystem: subsystem, category: "NetworkResponse")
-    } else {
-      // Return a valid logger that's using `OSLog.disabled` as the logger, hiding everything.
-      return Logger(.disabled)
-    }
-  }()
-
-  ///
-  static let verbose: Logger = {
-    if additionalLoggingEnabled() {
-      return Logger(subsystem: subsystem, category: defaultCategory)
-    } else {
-      // Return a valid logger that's using `OSLog.disabled` as the logger, hiding everything.
-      return Logger(.disabled)
-    }
-  }()
-
-  /// Returns `true` if additional logging has been enabled via a launch argument.
-  static func additionalLoggingEnabled() -> Bool {
-    let arguments = ProcessInfo.processInfo.arguments
-    if arguments.contains(enableArgumentKey) || arguments.contains(migrationEnableArgumentKey) {
-      return true
-    }
-    return false
-  }
-}
diff --git a/FirebaseVertexAI/Sources/ModelContent.swift b/FirebaseVertexAI/Sources/ModelContent.swift
index 3262a4eba15..f5699a600fb 100644
--- a/FirebaseVertexAI/Sources/ModelContent.swift
+++ b/FirebaseVertexAI/Sources/ModelContent.swift
@@ -26,7 +26,7 @@ public struct ModelContent: Equatable, Sendable {
     case text(String)
 
     /// Data with a specified media type. Not all media types may be supported by the AI model.
-    case data(mimetype: String, Data)
+    case inlineData(mimetype: String, Data)
 
     /// File data stored in Cloud Storage for Firebase, referenced by URI.
     ///
@@ -53,12 +53,12 @@ public struct ModelContent: Equatable, Sendable {
 
     /// Convenience function for populating a Part with JPEG data.
     public static func jpeg(_ data: Data) -> Self {
-      return .data(mimetype: "image/jpeg", data)
+      return .inlineData(mimetype: "image/jpeg", data)
     }
 
     /// Convenience function for populating a Part with PNG data.
     public static func png(_ data: Data) -> Self {
-      return .data(mimetype: "image/png", data)
+      return .inlineData(mimetype: "image/png", data)
     }
 
     /// Returns the text contents of this ``Part``, if it contains text.
@@ -144,7 +144,7 @@ extension ModelContent.Part: Codable {
     switch self {
     case let .text(a0):
       try container.encode(a0, forKey: .text)
-    case let .data(mimetype, bytes):
+    case let .inlineData(mimetype, bytes):
       var inlineDataContainer = container.nestedContainer(
         keyedBy: InlineDataKeys.self,
         forKey: .inlineData
@@ -176,7 +176,7 @@ extension ModelContent.Part: Codable {
       )
       let mimetype = try dataContainer.decode(String.self, forKey: .mimeType)
       let bytes = try dataContainer.decode(Data.self, forKey: .bytes)
-      self = .data(mimetype: mimetype, bytes)
+      self = .inlineData(mimetype: mimetype, bytes)
     } else if values.contains(.functionCall) {
       self = try .functionCall(values.decode(FunctionCall.self, forKey: .functionCall))
     } else if values.contains(.functionResponse) {
diff --git a/FirebaseVertexAI/Sources/PartsRepresentable+Image.swift b/FirebaseVertexAI/Sources/PartsRepresentable+Image.swift
index 1991503a224..6b2cc977889 100644
--- a/FirebaseVertexAI/Sources/PartsRepresentable+Image.swift
+++ b/FirebaseVertexAI/Sources/PartsRepresentable+Image.swift
@@ -24,29 +24,15 @@ private let imageCompressionQuality: CGFloat = 0.8
 /// An enum describing failures that can occur when converting image types to model content data.
 /// For some image types like `CIImage`, creating valid model content requires creating a JPEG
 /// representation of the image that may not yet exist, which may be computationally expensive.
-public enum ImageConversionError: Error {
-  /// The image that could not be converted.
-  public enum SourceImage {
-    #if canImport(UIKit)
-      case uiImage(UIImage)
-    #elseif canImport(AppKit)
-      case nsImage(NSImage)
-    #endif // canImport(UIKit)
-    case cgImage(CGImage)
-    #if canImport(CoreImage)
-      case ciImage(CIImage)
-    #endif // canImport(CoreImage)
-  }
-
+enum ImageConversionError: Error {
   /// The image (the receiver of the call `toModelContentParts()`) was invalid.
   case invalidUnderlyingImage
 
   /// A valid image destination could not be allocated.
   case couldNotAllocateDestination
 
-  /// JPEG image data conversion failed, accompanied by the original image, which may be an
-  /// instance of `NSImage`, `UIImage`, `CGImage`, or `CIImage`.
-  case couldNotConvertToJPEG(SourceImage)
+  /// JPEG image data conversion failed.
+  case couldNotConvertToJPEG
 }
 
 #if canImport(UIKit)
@@ -55,9 +41,9 @@ public enum ImageConversionError: Error {
   extension UIImage: ThrowingPartsRepresentable {
     public func tryPartsValue() throws -> [ModelContent.Part] {
       guard let data = jpegData(compressionQuality: imageCompressionQuality) else {
-        throw ImageConversionError.couldNotConvertToJPEG(.uiImage(self))
+        throw ImageConversionError.couldNotConvertToJPEG
       }
-      return [ModelContent.Part.data(mimetype: "image/jpeg", data)]
+      return [ModelContent.Part.inlineData(mimetype: "image/jpeg", data)]
     }
   }
 
@@ -72,9 +58,9 @@ public enum ImageConversionError: Error {
       let bmp = NSBitmapImageRep(cgImage: cgImage)
       guard let data = bmp.representation(using: .jpeg, properties: [.compressionFactor: 0.8])
       else {
-        throw ImageConversionError.couldNotConvertToJPEG(.nsImage(self))
+        throw ImageConversionError.couldNotConvertToJPEG
       }
-      return [ModelContent.Part.data(mimetype: "image/jpeg", data)]
+      return [ModelContent.Part.inlineData(mimetype: "image/jpeg", data)]
     }
   }
 #endif
@@ -95,9 +81,9 @@ public enum ImageConversionError: Error {
         kCGImageDestinationLossyCompressionQuality: imageCompressionQuality,
       ] as CFDictionary)
       if CGImageDestinationFinalize(imageDestination) {
-        return [.data(mimetype: "image/jpeg", output as Data)]
+        return [.inlineData(mimetype: "image/jpeg", output as Data)]
       }
-      throw ImageConversionError.couldNotConvertToJPEG(.cgImage(self))
+      throw ImageConversionError.couldNotConvertToJPEG
     }
   }
 #endif // !os(watchOS)
@@ -116,9 +102,9 @@ public enum ImageConversionError: Error {
           context.jpegRepresentation(of: self, colorSpace: $0, options: [:])
         }
       if let jpegData = jpegData {
-        return [.data(mimetype: "image/jpeg", jpegData)]
+        return [.inlineData(mimetype: "image/jpeg", jpegData)]
       }
-      throw ImageConversionError.couldNotConvertToJPEG(.ciImage(self))
+      throw ImageConversionError.couldNotConvertToJPEG
     }
   }
 #endif // canImport(CoreImage)
diff --git a/FirebaseVertexAI/Sources/Safety.swift b/FirebaseVertexAI/Sources/Safety.swift
index 6ad99bbb5e5..a57900e7317 100644
--- a/FirebaseVertexAI/Sources/Safety.swift
+++ b/FirebaseVertexAI/Sources/Safety.swift
@@ -19,18 +19,21 @@ import Foundation
 /// responses that exceed a certain threshold.
 @available(iOS 15.0, macOS 11.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
 public struct SafetyRating: Equatable, Hashable, Sendable {
-  /// The category describing the potential harm a piece of content may pose. See
-  /// ``SafetySetting/HarmCategory`` for a list of possible values.
-  public let category: SafetySetting.HarmCategory
-
-  /// The model-generated probability that a given piece of content falls under the harm category
-  /// described in ``SafetySetting/HarmCategory``. This does not indicate the severity of harm for a
-  /// piece of content. See ``HarmProbability`` for a list of possible values.
+  /// The category describing the potential harm a piece of content may pose.
+  ///
+  /// See ``HarmCategory`` for a list of possible values.
+  public let category: HarmCategory
+
+  /// The model-generated probability that the content falls under the specified harm ``category``.
+  ///
+  /// See ``HarmProbability`` for a list of possible values.
+  ///
+  /// > Important: This does not indicate the severity of harm for a piece of content.
   public let probability: HarmProbability
 
   /// Initializes a new `SafetyRating` instance with the given category and probability.
   /// Use this initializer for SwiftUI previews or tests.
-  public init(category: SafetySetting.HarmCategory, probability: HarmProbability) {
+  public init(category: HarmCategory, probability: HarmProbability) {
     self.category = category
     self.probability = probability
   }
@@ -41,9 +44,6 @@ public struct SafetyRating: Equatable, Hashable, Sendable {
     /// Unknown. A new server value that isn't recognized by the SDK.
     case unknown = "UNKNOWN"
 
-    /// The probability was not specified in the server response.
-    case unspecified = "HARM_PROBABILITY_UNSPECIFIED"
-
     /// The probability is zero or close to zero. For benign content, the probability across all
     /// categories will be this value.
     case negligible = "NEGLIGIBLE"
@@ -63,30 +63,8 @@ public struct SafetyRating: Equatable, Hashable, Sendable {
 /// fallback response instead of generated content.
 @available(iOS 15.0, macOS 11.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
 public struct SafetySetting {
-  /// A type describing safety attributes, which include harmful categories and topics that can
-  /// be considered sensitive.
-  public enum HarmCategory: String, Sendable {
-    /// Unknown. A new server value that isn't recognized by the SDK.
-    case unknown = "HARM_CATEGORY_UNKNOWN"
-
-    /// Unspecified by the server.
-    case unspecified = "HARM_CATEGORY_UNSPECIFIED"
-
-    /// Harassment content.
-    case harassment = "HARM_CATEGORY_HARASSMENT"
-
-    /// Negative or harmful comments targeting identity and/or protected attributes.
-    case hateSpeech = "HARM_CATEGORY_HATE_SPEECH"
-
-    /// Contains references to sexual acts or other lewd content.
-    case sexuallyExplicit = "HARM_CATEGORY_SEXUALLY_EXPLICIT"
-
-    /// Promotes or enables access to harmful goods, services, or activities.
-    case dangerousContent = "HARM_CATEGORY_DANGEROUS_CONTENT"
-  }
-
   /// Block at and beyond a specified ``SafetyRating/HarmProbability``.
-  public enum BlockThreshold: String, Sendable {
+  public enum HarmBlockThreshold: String, Sendable {
     // Content with `.negligible` will be allowed.
     case blockLowAndAbove = "BLOCK_LOW_AND_ABOVE"
 
@@ -109,15 +87,33 @@ public struct SafetySetting {
   public let harmCategory: HarmCategory
 
   /// The threshold describing what content should be blocked.
-  public let threshold: BlockThreshold
+  public let threshold: HarmBlockThreshold
 
   /// Initializes a new safety setting with the given category and threshold.
-  public init(harmCategory: HarmCategory, threshold: BlockThreshold) {
+  public init(harmCategory: HarmCategory, threshold: HarmBlockThreshold) {
     self.harmCategory = harmCategory
     self.threshold = threshold
   }
 }
 
+/// Categories describing the potential harm a piece of content may pose.
+public enum HarmCategory: String, Sendable {
+  /// Unknown. A new server value that isn't recognized by the SDK.
+  case unknown = "HARM_CATEGORY_UNKNOWN"
+
+  /// Harassment content.
+  case harassment = "HARM_CATEGORY_HARASSMENT"
+
+  /// Negative or harmful comments targeting identity and/or protected attributes.
+  case hateSpeech = "HARM_CATEGORY_HATE_SPEECH"
+
+  /// Contains references to sexual acts or other lewd content.
+  case sexuallyExplicit = "HARM_CATEGORY_SEXUALLY_EXPLICIT"
+
+  /// Promotes or enables access to harmful goods, services, or activities.
+  case dangerousContent = "HARM_CATEGORY_DANGEROUS_CONTENT"
+}
+
 // MARK: - Codable Conformances
 
 @available(iOS 15.0, macOS 11.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
@@ -125,8 +121,10 @@ extension SafetyRating.HarmProbability: Decodable {
   public init(from decoder: Decoder) throws {
     let value = try decoder.singleValueContainer().decode(String.self)
     guard let decodedProbability = SafetyRating.HarmProbability(rawValue: value) else {
-      Logging.default
-        .error("[FirebaseVertexAI] Unrecognized HarmProbability with value \"\(value)\".")
+      VertexLog.error(
+        code: .generateContentResponseUnrecognizedHarmProbability,
+        "Unrecognized HarmProbability with value \"\(value)\"."
+      )
       self = .unknown
       return
     }
@@ -139,12 +137,14 @@ extension SafetyRating.HarmProbability: Decodable {
 extension SafetyRating: Decodable {}
 
 @available(iOS 15.0, macOS 11.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
-extension SafetySetting.HarmCategory: Codable {
+extension HarmCategory: Codable {
   public init(from decoder: Decoder) throws {
     let value = try decoder.singleValueContainer().decode(String.self)
-    guard let decodedCategory = SafetySetting.HarmCategory(rawValue: value) else {
-      Logging.default
-        .error("[FirebaseVertexAI] Unrecognized HarmCategory with value \"\(value)\".")
+    guard let decodedCategory = HarmCategory(rawValue: value) else {
+      VertexLog.error(
+        code: .generateContentResponseUnrecognizedHarmCategory,
+        "Unrecognized HarmCategory with value \"\(value)\"."
+      )
       self = .unknown
       return
     }
@@ -154,7 +154,7 @@ extension SafetySetting.HarmCategory: Codable {
 }
 
 @available(iOS 15.0, macOS 11.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
-extension SafetySetting.BlockThreshold: Encodable {}
+extension SafetySetting.HarmBlockThreshold: Encodable {}
 
 @available(iOS 15.0, macOS 11.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
 extension SafetySetting: Encodable {}
diff --git a/FirebaseVertexAI/Sources/Schema.swift b/FirebaseVertexAI/Sources/Schema.swift
index 6ffadfd9025..f24a4d203b3 100644
--- a/FirebaseVertexAI/Sources/Schema.swift
+++ b/FirebaseVertexAI/Sources/Schema.swift
@@ -19,29 +19,45 @@ import Foundation
 /// These types can be objects, but also primitives and arrays. Represents a select subset of an
 /// [OpenAPI 3.0 schema object](https://spec.openapis.org/oas/v3.0.3#schema).
 public class Schema {
+  /// Modifiers describing the expected format of a string `Schema`.
+  public enum StringFormat {
+    /// A custom string format.
+    case custom(String)
+  }
+
+  /// Modifiers describing the expected format of an integer `Schema`.
+  public enum IntegerFormat {
+    /// A 32-bit signed integer.
+    case int32
+    /// A 64-bit signed integer.
+    case int64
+    /// A custom integer format.
+    case custom(String)
+  }
+
   /// The data type.
-  let type: DataType
+  public let type: DataType
 
   /// The format of the data.
-  let format: String?
+  public let format: String?
 
   /// A brief description of the parameter.
-  let description: String?
+  public let description: String?
 
   /// Indicates if the value may be null.
-  let nullable: Bool?
+  public let nullable: Bool?
 
   /// Possible values of the element of type ``DataType/string`` with "enum" format.
-  let enumValues: [String]?
+  public let enumValues: [String]?
 
   /// Schema of the elements of type ``DataType/array``.
-  let items: Schema?
+  public let items: Schema?
 
   /// Properties of type ``DataType/object``.
-  let properties: [String: Schema]?
+  public let properties: [String: Schema]?
 
   /// Required properties of type ``DataType/object``.
-  let requiredProperties: [String]?
+  public let requiredProperties: [String]?
 
   /// Constructs a new `Schema`.
   ///
@@ -59,11 +75,29 @@ public class Schema {
   ///   - items: Schema of the elements of type ``DataType/array``.
   ///   - properties: Properties of type ``DataType/object``.
   ///   - requiredProperties: Required properties of type ``DataType/object``.
-  public init(type: DataType, format: String? = nil, description: String? = nil,
-              nullable: Bool? = nil,
-              enumValues: [String]? = nil, items: Schema? = nil,
-              properties: [String: Schema]? = nil,
-              requiredProperties: [String]? = nil) {
+  @available(*, deprecated, message: """
+  Use static methods `string(description:format:nullable:)`, `number(description:format:nullable:)`,
+  etc., instead.
+  """)
+  public convenience init(type: DataType, format: String? = nil, description: String? = nil,
+                          nullable: Bool? = nil, enumValues: [String]? = nil, items: Schema? = nil,
+                          properties: [String: Schema]? = nil,
+                          requiredProperties: [String]? = nil) {
+    self.init(
+      type: type,
+      format: format,
+      description: description,
+      nullable: nullable ?? false,
+      enumValues: enumValues,
+      items: items,
+      properties: properties,
+      requiredProperties: requiredProperties
+    )
+  }
+
+  required init(type: DataType, format: String? = nil, description: String? = nil,
+                nullable: Bool = false, enumValues: [String]? = nil, items: Schema? = nil,
+                properties: [String: Schema]? = nil, requiredProperties: [String]? = nil) {
     self.type = type
     self.format = format
     self.description = description
@@ -73,6 +107,228 @@ public class Schema {
     self.properties = properties
     self.requiredProperties = requiredProperties
   }
+
+  /// Returns a `Schema` representing a string value.
+  ///
+  /// This schema instructs the model to produce data of type ``DataType/string``, which is suitable
+  /// for decoding into a Swift `String` (or `String?`, if `nullable` is set to `true`).
+  ///
+  /// > Tip: If a specific set of string values should be generated by the model (for example,
+  /// > "north", "south", "east", or "west"), use ``enumeration(values:description:nullable:)``
+  /// > instead to constrain the generated values.
+  ///
+  /// - Parameters:
+  ///   - description: An optional description of what the string should contain or represent; may
+  ///     use Markdown format.
+  ///   - nullable: If `true`, instructs the model that it *may* generate `null` instead of a
+  ///     string; defaults to `false`, enforcing that a string value is generated.
+  ///   - format: An optional modifier describing the expected format of the string. Currently no
+  ///     formats are officially supported for strings but custom values may be specified using
+  ///     ``StringFormat/custom(_:)``, for example `.custom("email")` or `.custom("byte")`; these
+  ///     provide additional hints for how the model should respond but are not guaranteed to be
+  ///     adhered to.
+  public static func string(description: String? = nil, nullable: Bool = false,
+                            format: StringFormat? = nil) -> Schema {
+    return self.init(
+      type: .string,
+      format: format?.rawValue,
+      description: description,
+      nullable: nullable
+    )
+  }
+
+  /// Returns a `Schema` representing an enumeration of string values.
+  ///
+  /// This schema instructs the model to produce data of type ``DataType/string`` with the
+  /// `format` `"enum"`. This data is suitable for decoding into a Swift `String` (or `String?`,
+  /// if `nullable` is set to `true`), or an `enum` with strings as raw values.
+  ///
+  /// **Example:**
+  /// The values `["north", "south", "east", "west"]` for an enumation of directions.
+  /// ```
+  /// enum Direction: String, Decodable {
+  ///   case north, south, east, west
+  /// }
+  /// ```
+  ///
+  /// - Parameters:
+  ///   - values: The list of string values that may be generated by the model.
+  ///   - description: An optional description of what the `values` contain or represent; may use
+  ///     Markdown format.
+  ///   - nullable: If `true`, instructs the model that it *may* generate `null` instead of one of
+  ///     the strings specified in `values`; defaults to `false`, enforcing that one of the string
+  ///     values is generated.
+  public static func enumeration(values: [String], description: String? = nil,
+                                 nullable: Bool = false) -> Schema {
+    return self.init(
+      type: .string,
+      format: "enum",
+      description: description,
+      nullable: nullable,
+      enumValues: values
+    )
+  }
+
+  /// Returns a `Schema` representing a single-precision floating-point number.
+  ///
+  /// This schema instructs the model to produce data of type ``DataType/number`` with the
+  /// `format` `"float"`, which is suitable for decoding into a Swift `Float` (or `Float?`, if
+  /// `nullable` is set to `true`).
+  ///
+  /// > Important: This `Schema` provides a hint to the model that it should generate a
+  /// > single-precision floating-point number, a `float`, but only guarantees that the value will
+  /// > be a number.
+  ///
+  /// - Parameters:
+  ///   - description: An optional description of what the number should contain or represent; may
+  ///     use Markdown format.
+  ///   - nullable: If `true`, instructs the model that it may generate `null` instead of a number;
+  ///     defaults to `false`, enforcing that a number is generated.
+  public static func float(description: String? = nil, nullable: Bool = false) -> Schema {
+    return self.init(
+      type: .number,
+      format: "float",
+      description: description,
+      nullable: nullable
+    )
+  }
+
+  /// Returns a `Schema` representing a double-precision floating-point number.
+  ///
+  /// This schema instructs the model to produce data of type ``DataType/number`` with the
+  /// `format` `"double"`, which is suitable for decoding into a Swift `Double` (or `Double?`, if
+  /// `nullable` is set to `true`).
+  ///
+  /// > Important: This `Schema` provides a hint to the model that it should generate a
+  /// > double-precision floating-point number, a `double`, but only guarantees that the value will
+  /// > be a number.
+  ///
+  /// - Parameters:
+  ///   - description: An optional description of what the number should contain or represent; may
+  ///     use Markdown format.
+  ///   - nullable: If `true`, instructs the model that it may return `null` instead of a number;
+  ///     defaults to `false`, enforcing that a number is returned.
+  public static func double(description: String? = nil, nullable: Bool = false) -> Schema {
+    return self.init(
+      type: .number,
+      format: "double",
+      description: description,
+      nullable: nullable
+    )
+  }
+
+  /// Returns a `Schema` representing an integer value.
+  ///
+  /// This schema instructs the model to produce data of type ``DataType/integer``, which is
+  /// suitable for decoding into a Swift `Int` (or `Int?`, if `nullable` is set to `true`) or other
+  /// integer types (such as `Int32`) based on the expected size of values being generated.
+  ///
+  /// > Important: If a `format` of ``IntegerFormat/int32`` or ``IntegerFormat/int64`` is
+  /// > specified, this provides a hint to the model that it should generate 32-bit or 64-bit
+  /// > integers but this `Schema` only guarantees that the value will be an integer. Therefore, it
+  /// > is *possible* that decoding into an `Int32` could overflow even if a `format` of
+  /// > ``IntegerFormat/int32`` is specified.
+  ///
+  /// - Parameters:
+  ///   - description: An optional description of what the integer should contain or represent; may
+  ///     use Markdown format.
+  ///   - nullable: If `true`, instructs the model that it may return `null` instead of an integer;
+  ///     defaults to `false`, enforcing that an integer is returned.
+  ///   - format: An optional modifier describing the expected format of the integer. Currently the
+  ///     formats ``IntegerFormat/int32`` and ``IntegerFormat/int64`` are supported; custom values
+  ///     may be specified using ``IntegerFormat/custom(_:)`` but may be ignored by the model.
+  public static func integer(description: String? = nil, nullable: Bool = false,
+                             format: IntegerFormat? = nil) -> Schema {
+    return self.init(
+      type: .integer,
+      format: format?.rawValue,
+      description: description,
+      nullable: nullable
+    )
+  }
+
+  /// Returns a `Schema` representing a boolean value.
+  ///
+  /// This schema instructs the model to produce data of type ``DataType/boolean``, which is
+  /// suitable for decoding into a Swift `Bool` (or `Bool?`, if `nullable` is set to `true`).
+  ///
+  /// - Parameters:
+  ///   - description: An optional description of what the boolean should contain or represent; may
+  ///   use Markdown format.
+  ///   - nullable: If `true`, instructs the model that it may return `null` instead of a boolean;
+  ///   defaults to `false`, enforcing that a boolean is returned.
+  public static func boolean(description: String? = nil, nullable: Bool = false) -> Schema {
+    return self.init(type: .boolean, description: description, nullable: nullable)
+  }
+
+  /// Returns a `Schema` representing an array.
+  ///
+  /// This schema instructs the model to produce data of type ``DataType/array``, which has elements
+  /// of any other ``DataType`` (including nested ``DataType/array``s). This data is suitable for
+  /// decoding into many Swift collection types, including `Array`, holding elements of types
+  /// suitable for decoding from the respective `items` type.
+  ///
+  /// - Parameters:
+  ///   - items: The `Schema` of the elements that the array will hold.
+  ///   - description: An optional description of what the array should contain or represent; may
+  ///   use Markdown format.
+  ///   - nullable: If `true`, instructs the model that it may return `null` instead of an array;
+  ///   defaults to `false`, enforcing that an array is returned.
+  public static func array(items: Schema, description: String? = nil,
+                           nullable: Bool = false) -> Schema {
+    return self.init(type: .array, description: description, nullable: nullable, items: items)
+  }
+
+  /// Returns a `Schema` representing an object.
+  ///
+  /// This schema instructs the model to produce data of type ``DataType/object``, which has keys
+  /// of type ``DataType/string`` and values of any other ``DataType`` (including nested
+  /// ``DataType/object``s). This data is suitable for decoding into Swift keyed collection types,
+  /// including `Dictionary`, or other custom `struct` or `class` types.
+  ///
+  /// **Example:** A `City` could be represented with the following object `Schema`.
+  /// ```
+  /// Schema.object(properties: [
+  ///   "name" : .string(),
+  ///   "population": .integer()
+  /// ])
+  /// ```
+  /// The generated data could be decoded into a Swift native type:
+  /// ```
+  /// struct City: Decodable {
+  ///   let name: String
+  ///   let population: Int
+  /// }
+  /// ```
+  ///
+  /// - Parameters:
+  ///   - properties: A dictionary containing the object's property names as keys and their
+  ///   respective `Schema`s as values.
+  ///   - optionalProperties: A list of property names that may be be omitted in objects generated
+  ///   by the model; these names must correspond to the keys provided in the `properties`
+  ///   dictionary and may be an empty list.
+  ///   - description: An optional description of what the object should contain or represent; may
+  ///   use Markdown format.
+  ///   - nullable: If `true`, instructs the model that it may return `null` instead of an object;
+  ///   defaults to `false`, enforcing that an object is returned.
+  public static func object(properties: [String: Schema], optionalProperties: [String] = [],
+                            description: String? = nil, nullable: Bool = false) -> Schema {
+    var requiredProperties = Set(properties.keys)
+    for optionalProperty in optionalProperties {
+      guard properties.keys.contains(optionalProperty) else {
+        fatalError("Optional property \"\(optionalProperty)\" not defined in object properties.")
+      }
+      requiredProperties.remove(optionalProperty)
+    }
+
+    return self.init(
+      type: .object,
+      description: description,
+      nullable: nullable,
+      properties: properties,
+      requiredProperties: requiredProperties.sorted()
+    )
+  }
 }
 
 /// A data type.
@@ -114,3 +370,45 @@ extension Schema: Encodable {
 }
 
 extension DataType: Encodable {}
+
+// MARK: - RawRepresentable Conformance
+
+extension Schema.IntegerFormat: RawRepresentable {
+  public init?(rawValue: String) {
+    switch rawValue {
+    case "int32":
+      self = .int32
+    case "int64":
+      self = .int64
+    default:
+      self = .custom(rawValue)
+    }
+  }
+
+  public var rawValue: String {
+    switch self {
+    case .int32:
+      return "int32"
+    case .int64:
+      return "int64"
+    case let .custom(format):
+      return format
+    }
+  }
+}
+
+extension Schema.StringFormat: RawRepresentable {
+  public init?(rawValue: String) {
+    switch rawValue {
+    default:
+      self = .custom(rawValue)
+    }
+  }
+
+  public var rawValue: String {
+    switch self {
+    case let .custom(format):
+      return format
+    }
+  }
+}
diff --git a/FirebaseVertexAI/Sources/VertexLog.swift b/FirebaseVertexAI/Sources/VertexLog.swift
new file mode 100644
index 00000000000..bd400c200c2
--- /dev/null
+++ b/FirebaseVertexAI/Sources/VertexLog.swift
@@ -0,0 +1,112 @@
+// Copyright 2024 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import Foundation
+import os.log
+
+@_implementationOnly import FirebaseCoreExtension
+
+enum VertexLog {
+  /// Log message codes for the Vertex AI SDK
+  ///
+  /// These codes should ideally not be re-used in order to facilitate matching error codes in
+  /// support requests to lines in the SDK. These codes should range between 0 and 999999 to avoid
+  /// being truncated in log messages.
+  enum MessageCode: Int {
+    // Logging Configuration
+    case verboseLoggingDisabled = 100
+    case verboseLoggingEnabled = 101
+
+    // API Enablement Errors
+    case vertexAIInFirebaseAPIDisabled = 200
+
+    // Model Configuration
+    case generativeModelInitialized = 1000
+
+    // Network Errors
+    case generativeAIServiceNonHTTPResponse = 2000
+    case loadRequestResponseError = 2001
+    case loadRequestResponseErrorPayload = 2002
+    case loadRequestStreamResponseError = 2003
+    case loadRequestStreamResponseErrorPayload = 2004
+
+    // Parsing Errors
+    case loadRequestParseResponseFailedJSON = 3000
+    case loadRequestParseResponseFailedJSONError = 3001
+    case generateContentResponseUnrecognizedFinishReason = 3002
+    case generateContentResponseUnrecognizedBlockReason = 3003
+    case generateContentResponseUnrecognizedBlockThreshold = 3004
+    case generateContentResponseUnrecognizedHarmProbability = 3005
+    case generateContentResponseUnrecognizedHarmCategory = 3006
+
+    // SDK State Errors
+    case generateContentResponseNoCandidates = 4000
+    case generateContentResponseNoText = 4001
+    case appCheckTokenFetchFailed = 4002
+
+    // SDK Debugging
+    case loadRequestStreamResponseLine = 5000
+  }
+
+  /// Subsystem that should be used for all Loggers.
+  static let subsystem = "com.google.firebase"
+
+  /// Log identifier for the Vertex AI SDK.
+  ///
+  /// > Note: This corresponds to the `category` in `OSLog`.
+  static let service = "[FirebaseVertexAI]"
+
+  /// The raw `OSLog` log object.
+  ///
+  /// > Important: This is only needed for direct `os_log` usage.
+  static let logObject = OSLog(subsystem: subsystem, category: service)
+
+  /// The argument required to enable additional logging.
+  static let enableArgumentKey = "-FIRDebugEnabled"
+
+  static func log(level: FirebaseLoggerLevel, code: MessageCode, _ message: String) {
+    let messageCode = String(format: "I-VTX%06d", code.rawValue)
+    FirebaseLogger.log(
+      level: level,
+      service: VertexLog.service,
+      code: messageCode,
+      message: message
+    )
+  }
+
+  static func error(code: MessageCode, _ message: String) {
+    log(level: .error, code: code, message)
+  }
+
+  static func warning(code: MessageCode, _ message: String) {
+    log(level: .warning, code: code, message)
+  }
+
+  static func notice(code: MessageCode, _ message: String) {
+    log(level: .notice, code: code, message)
+  }
+
+  static func info(code: MessageCode, _ message: String) {
+    log(level: .info, code: code, message)
+  }
+
+  static func debug(code: MessageCode, _ message: String) {
+    log(level: .debug, code: code, message)
+  }
+
+  /// Returns `true` if additional logging has been enabled via a launch argument.
+  static func additionalLoggingEnabled() -> Bool {
+    return ProcessInfo.processInfo.arguments.contains(enableArgumentKey)
+  }
+}
diff --git a/FirebaseVertexAI/Tests/Unit/GenerationConfigTests.swift b/FirebaseVertexAI/Tests/Unit/GenerationConfigTests.swift
index 35450c03758..43cbfe6dd96 100644
--- a/FirebaseVertexAI/Tests/Unit/GenerationConfigTests.swift
+++ b/FirebaseVertexAI/Tests/Unit/GenerationConfigTests.swift
@@ -57,7 +57,7 @@ final class GenerationConfigTests: XCTestCase {
       maxOutputTokens: maxOutputTokens,
       stopSequences: stopSequences,
       responseMIMEType: responseMIMEType,
-      responseSchema: Schema(type: .array, items: Schema(type: .string))
+      responseSchema: .array(items: .string())
     )
 
     let jsonData = try encoder.encode(generationConfig)
@@ -70,8 +70,10 @@ final class GenerationConfigTests: XCTestCase {
       "responseMIMEType" : "\(responseMIMEType)",
       "responseSchema" : {
         "items" : {
+          "nullable" : false,
           "type" : "STRING"
         },
+        "nullable" : false,
         "type" : "ARRAY"
       },
       "stopSequences" : [
@@ -89,15 +91,11 @@ final class GenerationConfigTests: XCTestCase {
     let mimeType = "application/json"
     let generationConfig = GenerationConfig(
       responseMIMEType: mimeType,
-      responseSchema: Schema(
-        type: .object,
-        properties: [
-          "firstName": Schema(type: .string),
-          "lastName": Schema(type: .string),
-          "age": Schema(type: .integer),
-        ],
-        requiredProperties: ["firstName", "lastName", "age"]
-      )
+      responseSchema: .object(properties: [
+        "firstName": .string(),
+        "lastName": .string(),
+        "age": .integer(),
+      ])
     )
 
     let jsonData = try encoder.encode(generationConfig)
@@ -107,21 +105,25 @@ final class GenerationConfigTests: XCTestCase {
     {
       "responseMIMEType" : "\(mimeType)",
       "responseSchema" : {
+        "nullable" : false,
         "properties" : {
           "age" : {
+            "nullable" : false,
             "type" : "INTEGER"
           },
           "firstName" : {
+            "nullable" : false,
             "type" : "STRING"
           },
           "lastName" : {
+            "nullable" : false,
             "type" : "STRING"
           }
         },
         "required" : [
+          "age",
           "firstName",
-          "lastName",
-          "age"
+          "lastName"
         ],
         "type" : "OBJECT"
       }
diff --git a/FirebaseVertexAI/Tests/Unit/GenerativeModelTests.swift b/FirebaseVertexAI/Tests/Unit/GenerativeModelTests.swift
index dc76123d028..6956160b072 100644
--- a/FirebaseVertexAI/Tests/Unit/GenerativeModelTests.swift
+++ b/FirebaseVertexAI/Tests/Unit/GenerativeModelTests.swift
@@ -113,20 +113,20 @@ final class GenerativeModelTests: XCTestCase {
     XCTAssertEqual(candidate.content.parts.count, 1)
     XCTAssertEqual(response.text, "Some information cited from an external source")
     let citationMetadata = try XCTUnwrap(candidate.citationMetadata)
-    XCTAssertEqual(citationMetadata.citationSources.count, 3)
-    let citationSource1 = try XCTUnwrap(citationMetadata.citationSources[0])
+    XCTAssertEqual(citationMetadata.citations.count, 3)
+    let citationSource1 = try XCTUnwrap(citationMetadata.citations[0])
     XCTAssertEqual(citationSource1.uri, "https://www.example.com/some-citation-1")
     XCTAssertEqual(citationSource1.startIndex, 0)
     XCTAssertEqual(citationSource1.endIndex, 128)
     XCTAssertNil(citationSource1.title)
     XCTAssertNil(citationSource1.license)
-    let citationSource2 = try XCTUnwrap(citationMetadata.citationSources[1])
+    let citationSource2 = try XCTUnwrap(citationMetadata.citations[1])
     XCTAssertEqual(citationSource2.title, "some-citation-2")
     XCTAssertEqual(citationSource2.startIndex, 130)
     XCTAssertEqual(citationSource2.endIndex, 265)
     XCTAssertNil(citationSource2.uri)
     XCTAssertNil(citationSource2.license)
-    let citationSource3 = try XCTUnwrap(citationMetadata.citationSources[2])
+    let citationSource3 = try XCTUnwrap(citationMetadata.citations[2])
     XCTAssertEqual(citationSource3.uri, "https://www.example.com/some-citation-3")
     XCTAssertEqual(citationSource3.startIndex, 272)
     XCTAssertEqual(citationSource3.endIndex, 431)
@@ -453,6 +453,7 @@ final class GenerativeModelTests: XCTestCase {
     }
   }
 
+  // TODO(andrewheard): Remove this test case after the Vertex AI in Firebase API launch.
   func testGenerateContent_failure_firebaseMLAPINotEnabled() async throws {
     let expectedStatusCode = 403
     MockURLProtocol
@@ -476,6 +477,30 @@ final class GenerativeModelTests: XCTestCase {
     }
   }
 
+  func testGenerateContent_failure_firebaseVertexAIAPINotEnabled() async throws {
+    let expectedStatusCode = 403
+    MockURLProtocol
+      .requestHandler = try httpRequestHandler(
+        forResource: "unary-failure-firebasevertexai-api-not-enabled",
+        withExtension: "json",
+        statusCode: expectedStatusCode
+      )
+
+    do {
+      _ = try await model.generateContent(testPrompt)
+      XCTFail("Should throw GenerateContentError.internalError; no error thrown.")
+    } catch let GenerateContentError.internalError(error as RPCError) {
+      XCTAssertEqual(error.httpResponseCode, expectedStatusCode)
+      XCTAssertEqual(error.status, .permissionDenied)
+      XCTAssertTrue(error.message
+        .starts(with: "Vertex AI in Firebase API has not been used in project"))
+      XCTAssertTrue(error.isVertexAIInFirebaseServiceDisabledError())
+      return
+    } catch {
+      XCTFail("Should throw GenerateContentError.internalError(RPCError); error thrown: \(error)")
+    }
+  }
+
   func testGenerateContent_failure_emptyContent() async throws {
     MockURLProtocol
       .requestHandler = try httpRequestHandler(
@@ -774,6 +799,7 @@ final class GenerativeModelTests: XCTestCase {
     XCTFail("Should have caught an error.")
   }
 
+  // TODO(andrewheard): Remove this test case after the Vertex AI in Firebase API launch.
   func testGenerateContentStream_failure_firebaseMLAPINotEnabled() async throws {
     let expectedStatusCode = 403
     MockURLProtocol
@@ -799,6 +825,32 @@ final class GenerativeModelTests: XCTestCase {
     XCTFail("Should have caught an error.")
   }
 
+  func testGenerateContentStream_failure_vertexAIInFirebaseAPINotEnabled() async throws {
+    let expectedStatusCode = 403
+    MockURLProtocol
+      .requestHandler = try httpRequestHandler(
+        forResource: "unary-failure-firebasevertexai-api-not-enabled",
+        withExtension: "json",
+        statusCode: expectedStatusCode
+      )
+
+    do {
+      let stream = try model.generateContentStream(testPrompt)
+      for try await _ in stream {
+        XCTFail("No content is there, this shouldn't happen.")
+      }
+    } catch let GenerateContentError.internalError(error as RPCError) {
+      XCTAssertEqual(error.httpResponseCode, expectedStatusCode)
+      XCTAssertEqual(error.status, .permissionDenied)
+      XCTAssertTrue(error.message
+        .starts(with: "Vertex AI in Firebase API has not been used in project"))
+      XCTAssertTrue(error.isVertexAIInFirebaseServiceDisabledError())
+      return
+    }
+
+    XCTFail("Should have caught an error.")
+  }
+
   func testGenerateContentStream_failureEmptyContent() async throws {
     MockURLProtocol
       .requestHandler = try httpRequestHandler(
@@ -947,7 +999,7 @@ final class GenerativeModelTests: XCTestCase {
       responses.append(content)
       XCTAssertNotNil(content.text)
       let candidate = try XCTUnwrap(content.candidates.first)
-      if let sources = candidate.citationMetadata?.citationSources {
+      if let sources = candidate.citationMetadata?.citations {
         citations.append(contentsOf: sources)
       }
     }
@@ -1188,13 +1240,13 @@ final class GenerativeModelTests: XCTestCase {
       withExtension: "json"
     )
 
-    let response = try await model.countTokens(ModelContent.Part.data(
+    let response = try await model.countTokens(ModelContent.Part.inlineData(
       mimetype: "image/jpeg",
       Data()
     ))
 
     XCTAssertEqual(response.totalTokens, 258)
-    XCTAssertEqual(response.totalBillableCharacters, 0)
+    XCTAssertNil(response.totalBillableCharacters)
   }
 
   func testCountTokens_modelNotFound() async throws {
@@ -1206,7 +1258,7 @@ final class GenerativeModelTests: XCTestCase {
     do {
       _ = try await model.countTokens("Why is the sky blue?")
       XCTFail("Request should not have succeeded.")
-    } catch let CountTokensError.internalError(rpcError as RPCError) {
+    } catch let rpcError as RPCError {
       XCTAssertEqual(rpcError.httpResponseCode, 404)
       XCTAssertEqual(rpcError.status, .notFound)
       XCTAssert(rpcError.message.hasPrefix("models/test-model-name is not found"))
@@ -1267,7 +1319,7 @@ final class GenerativeModelTests: XCTestCase {
   private func httpRequestHandler(forResource name: String,
                                   withExtension ext: String,
                                   statusCode: Int = 200,
-                                  timeout: TimeInterval = URLRequest.defaultTimeoutInterval(),
+                                  timeout: TimeInterval = RequestOptions().timeout,
                                   appCheckToken: String? = nil,
                                   authToken: String? = nil) throws -> ((URLRequest) throws -> (
     URLResponse,
@@ -1316,14 +1368,6 @@ private extension String {
   }
 }
 
-private extension URLRequest {
-  /// Returns the default `timeoutInterval` for a `URLRequest`.
-  static func defaultTimeoutInterval() -> TimeInterval {
-    let placeholderURL = URL(string: "https://example.com")!
-    return URLRequest(url: placeholderURL).timeoutInterval
-  }
-}
-
 @available(iOS 15.0, macOS 12.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
 class AppCheckInteropFake: NSObject, AppCheckInterop {
   /// The placeholder token value returned when an error occurs
diff --git a/FirebaseVertexAI/Tests/Unit/PartsRepresentableTests.swift b/FirebaseVertexAI/Tests/Unit/PartsRepresentableTests.swift
index bd539d825a8..073f6582721 100644
--- a/FirebaseVertexAI/Tests/Unit/PartsRepresentableTests.swift
+++ b/FirebaseVertexAI/Tests/Unit/PartsRepresentableTests.swift
@@ -13,7 +13,6 @@
 // limitations under the License.
 
 import CoreGraphics
-import FirebaseVertexAI
 import XCTest
 #if canImport(UIKit)
   import UIKit
@@ -24,6 +23,8 @@ import XCTest
   import CoreImage
 #endif // canImport(CoreImage)
 
+@testable import FirebaseVertexAI
+
 @available(iOS 15.0, macOS 11.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
 final class PartsRepresentableTests: XCTestCase {
   #if !os(watchOS)
@@ -61,22 +62,13 @@ final class PartsRepresentableTests: XCTestCase {
       do {
         _ = try image.tryPartsValue()
         XCTFail("Expected model content from invalid image to error")
-      } catch {
-        guard let imageError = (error as? ImageConversionError) else {
-          XCTFail("Got unexpected error type: \(error)")
-          return
-        }
-        switch imageError {
-        case let .couldNotConvertToJPEG(source):
-          guard case let .ciImage(ciImage) = source else {
-            XCTFail("Unexpected image source: \(source)")
-            return
-          }
-          XCTAssertEqual(ciImage, image)
-        default:
-          XCTFail("Expected image conversion error, got \(imageError) instead")
+      } catch let imageError as ImageConversionError {
+        guard case .couldNotConvertToJPEG = imageError else {
+          XCTFail("Expected JPEG conversion error, got \(imageError) instead.")
           return
         }
+      } catch {
+        XCTFail("Got unexpected error type: \(error)")
       }
     }
   #endif // canImport(CoreImage)
@@ -87,22 +79,13 @@ final class PartsRepresentableTests: XCTestCase {
       do {
         _ = try image.tryPartsValue()
         XCTFail("Expected model content from invalid image to error")
-      } catch {
-        guard let imageError = (error as? ImageConversionError) else {
-          XCTFail("Got unexpected error type: \(error)")
-          return
-        }
-        switch imageError {
-        case let .couldNotConvertToJPEG(source):
-          guard case let .uiImage(uiImage) = source else {
-            XCTFail("Unexpected image source: \(source)")
-            return
-          }
-          XCTAssertEqual(uiImage, image)
-        default:
-          XCTFail("Expected image conversion error, got \(imageError) instead")
+      } catch let imageError as ImageConversionError {
+        guard case .couldNotConvertToJPEG = imageError else {
+          XCTFail("Expected JPEG conversion error, got \(imageError) instead.")
           return
         }
+      } catch {
+        XCTFail("Got unexpected error type: \(error)")
       }
     }
 
diff --git a/FirebaseVertexAI/Tests/Unit/VertexAIAPITests.swift b/FirebaseVertexAI/Tests/Unit/VertexAIAPITests.swift
index c68b69b03ec..1c469867f76 100644
--- a/FirebaseVertexAI/Tests/Unit/VertexAIAPITests.swift
+++ b/FirebaseVertexAI/Tests/Unit/VertexAIAPITests.swift
@@ -123,7 +123,7 @@ final class VertexAIAPITests: XCTestCase {
     // convert value of type 'String' to expected element type
     // 'Array<ModelContent.Part>.ArrayLiteralElement'. Not sure if there's a way we can get it to
     // work.
-    let _ = try ModelContent(parts: [str, ModelContent.Part.data(
+    let _ = try ModelContent(parts: [str, ModelContent.Part.inlineData(
       mimetype: "foo",
       Data()
     )] as [any ThrowingPartsRepresentable])