firebase · daymxn · Apr 28, 2026 · Mar 10, 2026 · Mar 10, 2026 · Mar 10, 2026
diff --git a/FirebaseAI/CHANGELOG.md b/FirebaseAI/CHANGELOG.md
@@ -7,7 +7,13 @@
 - [fixed] Fixed a `no member 'autoFunctionDeclaration'` compilation error on
  unofficially supported Xcode versions older than 26.2. (#16037)
 - [fixed] Fixed missing thought summary output in `GenerativeModelSession.streamResponse`. (#16075)
- [fixed] Removed unnecessary log statements related to retrieving text parts during automatic function calling.
+- [fixed] Removed unnecessary log statements related to retrieving text parts during automatic function calling. (#16087, #16122)
+- [feature] Adds support for configuring image generation properties,
+  such as aspect ratio and image size, through the new `ImageConfig` struct
+  and its integration with `GenerationConfig`. (#15923)
+- [feature] Adds support for new `FinishReason` values including
+  image-related reasons like `imageSafety`, `noImage`, and others for
+  tool-use, language, and malformed responses. (#15931)

 # 12.12.0
 - [feature] Added support for automatic function calling in

diff --git a/FirebaseAI/Sources/GenerateContentResponse.swift b/FirebaseAI/Sources/GenerateContentResponse.swift
@@ -197,6 +197,9 @@ public struct Candidate: Sendable {
  /// generated a predefined stop sequence.
  public let finishReason: FinishReason?

+  /// A human-readable description of why the model stopped generating content, if it exists.
+  public let finishMessage: String?
+
  /// Cited works in the model's response content, if it exists.
  public let citationMetadata: CitationMetadata?

@@ -208,10 +211,11 @@ public struct Candidate: Sendable {
  /// Initializer for SwiftUI previews or tests.
  public init(content: ModelContent, safetyRatings: [SafetyRating], finishReason: FinishReason?,
              citationMetadata: CitationMetadata?, groundingMetadata: GroundingMetadata? = nil,
-              urlContextMetadata: URLContextMetadata? = nil) {
+              urlContextMetadata: URLContextMetadata? = nil, finishMessage: String? = nil) {
    self.content = content
    self.safetyRatings = safetyRatings
    self.finishReason = finishReason
+    self.finishMessage = finishMessage
    self.citationMetadata = citationMetadata
    self.groundingMetadata = groundingMetadata
    self.urlContextMetadata = urlContextMetadata
@@ -220,7 +224,8 @@ public struct Candidate: Sendable {
  // Returns `true` if the candidate contains no information that a developer could use.
  var isEmpty: Bool {
    content.parts
-      .isEmpty && finishReason == nil && citationMetadata == nil && groundingMetadata == nil &&
+      .isEmpty && finishReason == nil && finishMessage == nil && citationMetadata == nil &&
+      groundingMetadata == nil &&
      urlContextMetadata == nil
  }
 }
@@ -280,6 +285,16 @@ public struct FinishReason: DecodableProtoEnum, Hashable, Sendable {
    case prohibitedContent = "PROHIBITED_CONTENT"
    case spii = "SPII"
    case malformedFunctionCall = "MALFORMED_FUNCTION_CALL"
+    case imageSafety = "IMAGE_SAFETY"
+    case imageProhibitedContent = "IMAGE_PROHIBITED_CONTENT"
+    case imageOther = "IMAGE_OTHER"
+    case noImage = "NO_IMAGE"
+    case imageRecitation = "IMAGE_RECITATION"
+    case language = "LANGUAGE"
+    case unexpectedToolCall = "UNEXPECTED_TOOL_CALL"
+    case tooManyToolCalls = "TOO_MANY_TOOL_CALLS"
+    case missingThoughtSignature = "MISSING_THOUGHT_SIGNATURE"
+    case malformedResponse = "MALFORMED_RESPONSE"
  }

  /// Natural stop point of the model or provided stop sequence.
@@ -312,6 +327,36 @@ public struct FinishReason: DecodableProtoEnum, Hashable, Sendable {
  /// Token generation was stopped because the function call generated by the model was invalid.
  public static let malformedFunctionCall = FinishReason(kind: .malformedFunctionCall)

+  /// Token generation stopped because generated images contain safety violations.
+  public static let imageSafety = FinishReason(kind: .imageSafety)
+
+  /// Image generation stopped because generated images have other prohibited content.
+  public static let imageProhibitedContent = FinishReason(kind: .imageProhibitedContent)
+
+  /// Image generation stopped because of other miscellaneous issue.
+  public static let imageOther = FinishReason(kind: .imageOther)
+
+  /// The model was expected to generate an image, but none was generated.
+  public static let noImage = FinishReason(kind: .noImage)
+
+  /// Image generation stopped due to recitation.
+  public static let imageRecitation = FinishReason(kind: .imageRecitation)
+
+  /// The response candidate content was flagged for using an unsupported language.
+  public static let language = FinishReason(kind: .language)
+
+  /// Model generated a tool call but no tools were enabled in the request.
+  public static let unexpectedToolCall = FinishReason(kind: .unexpectedToolCall)
+
+  /// Model called too many tools consecutively, thus the system exited execution.
+  public static let tooManyToolCalls = FinishReason(kind: .tooManyToolCalls)
+
+  /// Request has at least one thought signature missing.
+  public static let missingThoughtSignature = FinishReason(kind: .missingThoughtSignature)
+
+  /// Finished due to malformed response.
+  public static let malformedResponse = FinishReason(kind: .malformedResponse)
+
  /// Returns the raw string representation of the `FinishReason` value.
  ///
  /// > Note: This value directly corresponds to the values in the [REST
@@ -558,6 +603,7 @@ extension Candidate: Decodable {
    case content
    case safetyRatings
    case finishReason
+    case finishMessage
    case citationMetadata
    case groundingMetadata
    case urlContextMetadata
@@ -592,6 +638,7 @@ extension Candidate: Decodable {
    }

    finishReason = try container.decodeIfPresent(FinishReason.self, forKey: .finishReason)
+    finishMessage = try container.decodeIfPresent(String.self, forKey: .finishMessage)

    citationMetadata = try container.decodeIfPresent(
      CitationMetadata.self,

diff --git a/FirebaseAI/Tests/TestApp/Tests/Integration/GenerateContentIntegrationTests.swift b/FirebaseAI/Tests/TestApp/Tests/Integration/GenerateContentIntegrationTests.swift
@@ -470,6 +470,44 @@ struct GenerateContentIntegrationTests {
    #endif // canImport(UIKit)
  }

+  @Test(arguments: [
+    (InstanceConfig.vertexAI_v1beta, ModelNames.gemini2_5_FlashImage),
+    (InstanceConfig.vertexAI_v1beta_global, ModelNames.gemini2_5_FlashImage),
+    (InstanceConfig.googleAI_v1beta, ModelNames.gemini2_5_FlashImage),
+    (InstanceConfig.googleAI_v1beta, ModelNames.gemini3_1_FlashImagePreview),
+    (InstanceConfig.vertexAI_v1beta_global, ModelNames.gemini3_1_FlashImagePreview),
+  ])
+  func generateContent_finishReason_imageSafety(_ config: InstanceConfig,
+                                                modelName: String) async throws {
+    let generationConfig = GenerationConfig(
+      responseModalities: [.image]
+    )
+    let model = FirebaseAI.componentInstance(config).generativeModel(
+      modelName: modelName,
+      generationConfig: generationConfig,
+    )
+    let prompt = "A graphic image of violence" // This prompt should trigger safety violation
+
+    do {
+      let response = try await model.generateContent(prompt)
+
+      // vertexAI gemini3_1_FlashImagePreview doesn't throw.
+      let candidate = try #require(response.candidates.first)
+      #expect(candidate.finishReason == .stop)
+    } catch {
+      guard let error = error as? GenerateContentError else {
+        Issue.record("Expected a \(GenerateContentError.self); got \(error.self).")
+        throw error
+      }
+      guard case let .responseStoppedEarly(reason, response) = error else {
+        Issue.record("Expected a GenerateContentError.responseStoppedEarly; got \(error.self).")
+        throw error
+      }
+      #expect(reason == .imageSafety || reason == .noImage)
+      #expect(response.candidates.first?.content.parts.isEmpty == true) // Ensure no content
+    }
+  }
+
  @Test(arguments: [
    (InstanceConfig.vertexAI_v1beta, ModelNames.gemini2_5_FlashImage),
    (InstanceConfig.vertexAI_v1beta_global, ModelNames.gemini2_5_FlashImage),

diff --git a/FirebaseAI/Tests/Unit/APITests.swift b/FirebaseAI/Tests/Unit/APITests.swift
@@ -232,4 +232,61 @@ final class APITests: XCTestCase {
    XCTAssertEqual(cacheDetail?.modality, .text)
    XCTAssertEqual(cacheDetail?.tokenCount, 50)
  }
+
+  func testFinishReason_decoding() throws {
+    let decoder = JSONDecoder()
+    let testCases: [FinishReason] = [
+      .language,
+      .unexpectedToolCall,
+      .tooManyToolCalls,
+      .missingThoughtSignature,
+      .malformedResponse,
+      .imageSafety,
+      .imageProhibitedContent,
+      .imageOther,
+      .noImage,
+      .imageRecitation,
+    ]
+
+    for expectedReason in testCases {
+      let reasonString = expectedReason.rawValue
+      let json = createResponseJSON(finishReason: reasonString)
+      let response = try decoder.decode(GenerateContentResponse.self, from: json)
+      XCTAssertEqual(
+        response.candidates.first?.finishReason,
+        expectedReason,
+        "Failed to decode finishReason '\(reasonString)'"
+      )
+    }
+  }
+
+  // Helper function to create JSON for GenerateContentResponse with a specific finish reason
+  private func createResponseJSON(finishReason: String) -> Data {
+    return """
+    {
+      "candidates": [
+        {
+          "content": {
+            "parts": [
+              { "text": "Test reply" }
+            ],
+            "role": "model"
+          },
+          "finishReason": "\(finishReason)",
+          "index": 0,
+          "safetyRatings": []
+        }
+      ],
+      "usageMetadata": {
+        "promptTokenCount": 10,
+        "cachedContentTokenCount": 0,
+        "candidatesTokenCount": 5,
+        "totalTokenCount": 15,
+        "promptTokensDetails": [],
+        "cacheTokensDetails": [],
+        "candidatesTokensDetails": []
+      }
+    }
+    """.data(using: .utf8)!
+  }
 }
diff --git a/FirebaseAI/Tests/Unit/Types/GenerateContentResponseTests.swift b/FirebaseAI/Tests/Unit/Types/GenerateContentResponseTests.swift
@@ -252,6 +252,22 @@ final class GenerateContentResponseTests: XCTestCase {
    XCTAssertEqual(candidate.finishReason, .stop)
  }

+  func testDecodeCandidate_withFinishMessage() throws {
+    let json = """
+    {
+      "content": { "role": "model", "parts": [ { "text": "Some text." } ] },
+      "finishReason": "STOP",
+      "finishMessage": "Stopped due to something."
+    }
+    """
+    let jsonData = try XCTUnwrap(json.data(using: .utf8))
+
+    let candidate = try jsonDecoder.decode(Candidate.self, from: jsonData)
+
+    XCTAssertEqual(candidate.finishMessage, "Stopped due to something.")
+    XCTAssertEqual(candidate.finishReason, .stop)
+  }
+
  // MARK: - Candidate.isEmpty

  func testCandidateIsEmpty_allEmpty_isTrue() throws {
@@ -287,4 +303,21 @@ final class GenerateContentResponseTests: XCTestCase {
      "A candidate with only `urlContextMetadata` should not be empty."
    )
  }
+
+  func testCandidateIsEmpty_withFinishMessage_isFalse() throws {
+    let candidate = Candidate(
+      content: ModelContent(parts: []),
+      safetyRatings: [],
+      finishReason: nil,
+      citationMetadata: nil,
+      groundingMetadata: nil,
+      urlContextMetadata: nil,
+      finishMessage: "Stopped"
+    )
+
+    XCTAssertFalse(
+      candidate.isEmpty,
+      "A candidate with only `finishMessage` should not be empty."
+    )
+  }
 }