[Firebase AI] Add URLContext tool

Author: andrewheard

FirebaseAI/Sources/Tool.swift

@@ -63,6 +63,11 @@ public struct GoogleSearch: Sendable {
   public init() {}
 }
 
+@available(iOS 15.0, macOS 12.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
+public struct URLContext: Sendable {
+  public init() {}
+}
+
 /// A helper tool that the model may use when generating responses.
 ///
 /// A `Tool` is a piece of code that enables the system to interact with external systems to perform
@@ -74,14 +79,24 @@ public struct Tool: Sendable {
   /// Specifies the Google Search configuration.
   let googleSearch: GoogleSearch?
 
+  let urlContext: URLContext?
+
   init(functionDeclarations: [FunctionDeclaration]?) {
     self.functionDeclarations = functionDeclarations
     googleSearch = nil
+    urlContext = nil
   }
 
   init(googleSearch: GoogleSearch) {
     self.googleSearch = googleSearch
     functionDeclarations = nil
+    urlContext = nil
+  }
+
+  init(urlContext: URLContext) {
+    self.urlContext = urlContext
+    functionDeclarations = nil
+    googleSearch = nil
   }
 
   /// Creates a tool that allows the model to perform function calling.
@@ -126,6 +141,10 @@ public struct Tool: Sendable {
   public static func googleSearch(_ googleSearch: GoogleSearch = GoogleSearch()) -> Tool {
     return self.init(googleSearch: googleSearch)
   }
+
+  public static func urlContext(_ urlContext: URLContext = URLContext()) -> Tool {
+    return self.init(urlContext: urlContext)
+  }
 }
 
 /// Configuration for specifying function calling behavior.
@@ -214,5 +233,8 @@ extension FunctionCallingConfig.Mode: Encodable {}
 @available(iOS 15.0, macOS 12.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
 extension GoogleSearch: Encodable {}
 
+@available(iOS 15.0, macOS 12.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
+extension URLContext: Encodable {}
+
 @available(iOS 15.0, macOS 12.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
 extension ToolConfig: Encodable {}

FirebaseAI/Tests/TestApp/Tests/Integration/GenerateContentIntegrationTests.swift

@@ -291,6 +291,44 @@ struct GenerateContentIntegrationTests {
     }
   }
 
+  @Test(
+    "generateContent with URL Context",
+    arguments: InstanceConfig.allConfigs
+  )
+  func generateContent_withURLContext_succeeds(_ config: InstanceConfig) async throws {
+    let model = FirebaseAI.componentInstance(config).generativeModel(
+      modelName: ModelNames.gemini2_5_Flash,
+      tools: [.urlContext()]
+    )
+    let prompt = """
+    Write a one paragraph summary of this blog post: \
+    https://developers.googleblog.com/en/introducing-gemma-3-270m/
+    """
+
+    let response = try await model.generateContent(prompt)
+
+    let candidate = try #require(response.candidates.first)
+    let groundingMetadata = try #require(candidate.groundingMetadata)
+    #expect(!groundingMetadata.groundingChunks.isEmpty)
+    #expect(!groundingMetadata.groundingSupports.isEmpty)
+
+    for chunk in groundingMetadata.groundingChunks {
+      #expect(chunk.web != nil)
+    }
+
+    for support in groundingMetadata.groundingSupports {
+      let segment = support.segment
+      #expect(segment.endIndex > segment.startIndex)
+      #expect(!segment.text.isEmpty)
+      #expect(!support.groundingChunkIndices.isEmpty)
+
+      // Ensure indices point to valid chunks
+      for index in support.groundingChunkIndices {
+        #expect(index < groundingMetadata.groundingChunks.count)
+      }
+    }
+  }
+
   // MARK: Streaming Tests
 
   @Test(arguments: [