[Firebase AI] Add support for JsonSchema

docs/readme.md

@@ -114,6 +114,7 @@ Release Notes
     - Firebase AI: All Imagen models are deprecated and will shut down as early
       as June 2026. As a replacement, you can
       [migrate your apps to use Gemini Image models (the "Nano Banana" models)](https://firebase.google.com/docs/ai-logic/imagen-models-migration).
+    - Firebase AI: Add support for the JsonSchema formatting.
 
 ### 13.9.0
 -   Changes

firebaseai/src/FunctionCalling.cs

@@ -40,6 +40,7 @@ public readonly struct FunctionDeclaration
     private string Name { get; }
     private string Description { get; }
     private Schema Parameters { get; }
+    private JsonSchema JsonParameters { get; }
 
     /// <summary>
     /// Constructs a new `FunctionDeclaration`.
@@ -57,6 +58,26 @@ public FunctionDeclaration(string name, string description,
       Name = name;
       Description = description;
       Parameters = Schema.Object(parameters, optionalParameters);
+      JsonParameters = null;
+    }
+
+    /// <summary>
+    /// Constructs a new `FunctionDeclaration`.
+    /// </summary>
+    /// <param name="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.</param>
+    /// <param name="description">A brief description of the function.</param>
+    /// <param name="parameters">Describes the parameters to this function.</param>
+    /// <param name="optionalParameters">The names of parameters that may be omitted by the model
+    ///   in function calls; by default, all parameters are considered required.</param>
+    public FunctionDeclaration(string name, string description,
+        IDictionary<string, JsonSchema> parameters,
+        IEnumerable<string> optionalParameters = null)
+    {
+      Name = name;
+      Description = description;
+      Parameters = null;
+      JsonParameters = JsonSchema.Object(parameters, optionalParameters);
     }
 
     /// <summary>
@@ -65,11 +86,21 @@ public FunctionDeclaration(string name, string description,
     /// </summary>
     internal Dictionary<string, object> ToJson()
     {
-      return new() {
+      var json = new Dictionary<string, object>() {
       { "name", Name },
       { "description", Description },
-      { "parameters", Parameters.ToJson() },
     };
+      // Only one of these will likely be set, but just check
+      if (JsonParameters != null)
+      {
+        json["parametersJsonSchema"] = JsonParameters.ToJson();
+      }
+      if (Parameters != null)
+      {
+        json["parameters"] = Parameters.ToJson();
+      }
+
+      return json;
     }
   }
 

firebaseai/src/GenerationConfig.cs

@@ -37,6 +37,7 @@ public readonly struct GenerationConfig
     private readonly string[] _stopSequences;
     private readonly string _responseMimeType;
     private readonly Schema _responseSchema;
+    private readonly JsonSchema _responseJsonSchema;
     private readonly List<ResponseModality> _responseModalities;
     private readonly ThinkingConfig? _thinkingConfig;
 
@@ -133,7 +134,7 @@ public readonly struct GenerationConfig
     /// `responseSchema`.</param>
     /// 
     /// <param name="responseSchema">Output schema of the generated candidate text. If set, a compatible
-    /// `responseMimeType` must also be set.
+    /// `responseMimeType` must also be set. Note that if this is set, responseJsonSchema should be left null.
     ///
     /// Compatible MIME types:
     /// - `application/json`: Schema for JSON response.
@@ -142,6 +143,16 @@ public readonly struct GenerationConfig
     /// [Control generated output](https://cloud.google.com/vertex-ai/generative-ai/docs/multimodal/control-generated-output)
     /// guide for more details.</param>
     /// 
+    /// <param name="responseJsonSchema">Output JSON schema of the generated candidate text. If set, a compatible
+    /// `responseMimeType` must also be set. Note that if this is set, responseSchema should be left null.
+    ///
+    /// Compatible MIME types:
+    /// - `application/json`: JsonSchema for JSON response.
+    ///
+    /// Refer to the
+    /// [Control generated output](https://cloud.google.com/vertex-ai/generative-ai/docs/multimodal/control-generated-output)
+    /// guide for more details.</param>
+    /// 
     /// <param name="responseModalities">
     /// The data types (modalities) that may be returned in model responses.
     ///
@@ -168,6 +179,7 @@ public GenerationConfig(
         string[] stopSequences = null,
         string responseMimeType = null,
         Schema responseSchema = null,
+        JsonSchema responseJsonSchema = null,
         IEnumerable<ResponseModality> responseModalities = null,
         ThinkingConfig? thinkingConfig = null)
     {
@@ -181,6 +193,7 @@ public GenerationConfig(
       _stopSequences = stopSequences;
       _responseMimeType = responseMimeType;
       _responseSchema = responseSchema;
+      _responseJsonSchema = responseJsonSchema;
       _responseModalities = responseModalities != null ?
           new List<ResponseModality>(responseModalities) : null;
       _thinkingConfig = thinkingConfig;
@@ -203,6 +216,7 @@ internal Dictionary<string, object> ToJson()
       if (_stopSequences != null && _stopSequences.Length > 0) jsonDict["stopSequences"] = _stopSequences;
       if (!string.IsNullOrWhiteSpace(_responseMimeType)) jsonDict["responseMimeType"] = _responseMimeType;
       if (_responseSchema != null) jsonDict["responseSchema"] = _responseSchema.ToJson();
+      if (_responseJsonSchema != null) jsonDict["responseJsonSchema"] = _responseJsonSchema.ToJson();
       if (_responseModalities != null && _responseModalities.Count > 0)
       {
         jsonDict["responseModalities"] =