fix: flatten TaskPushNotificationConfig to match v1 spec

samples/A2ACli/Host/A2ACli.cs

@@ -220,8 +220,10 @@ private static async Task<bool> CompleteTaskAsync(
         // Add push notification configuration if enabled
         if (usePushNotifications)
         {
-            payload.Configuration.PushNotificationConfig = new PushNotificationConfig
+            payload.Configuration.TaskPushNotificationConfig = new TaskPushNotificationConfig
             {
+                Id = Guid.NewGuid().ToString(),
+                TaskId = taskId,
                 Url = $"http://{notificationReceiverHost}:{notificationReceiverPort}/notify",
                 Authentication = new AuthenticationInfo
                 {

src/A2A.AspNetCore/A2AHttpProcessor.cs

@@ -201,9 +201,14 @@ internal static Task<IResult> CreatePushNotificationConfigRestAsync(
         {
             var request = new CreateTaskPushNotificationConfigRequest
             {
-                TaskId = taskId,
-                Config = config,
-                ConfigId = config.Id ?? string.Empty,
+                Config = new TaskPushNotificationConfig
+                {
+                    Id = config.Id ?? string.Empty,
+                    TaskId = taskId,
+                    Url = config.Url,
+                    Token = config.Token,
+                    Authentication = config.Authentication,
+                },
             };
             var result = await requestHandler.CreateTaskPushNotificationConfigAsync(request, ct).ConfigureAwait(false);
             return new A2AResponseResult(result);

src/A2A.V0_3Compat/V03ClientAdapter.cs

@@ -94,8 +94,8 @@ internal V03ClientAdapter(V03.A2AClient v03Client)
     {
         var v03Config = new V03.TaskPushNotificationConfig
         {
-            TaskId = request.TaskId,
-            PushNotificationConfig = V03TypeConverter.ToV03PushNotificationConfig(request.Config),
+            TaskId = request.Config.TaskId ?? string.Empty,
+            PushNotificationConfig = V03TypeConverter.ToV03PushNotificationConfigFromTask(request.Config),
         };
         var v03Result = await _v03Client.SetPushNotificationAsync(v03Config, cancellationToken).ConfigureAwait(false);
         return V03TypeConverter.ToV1TaskPushNotificationConfig(v03Result);

src/A2A.V0_3Compat/V03ServerProcessor.cs

@@ -367,14 +367,13 @@ private static async Task<IResult> HandleSingleAsync(
                 var v03Config = DeserializeParams<V03.TaskPushNotificationConfig>(rpcRequest.Params.Value);
                 var v1Request = new CreateTaskPushNotificationConfigRequest
                 {
-                    TaskId = v03Config.TaskId,
-                    Config = V03TypeConverter.ToV1PushNotificationConfig(v03Config.PushNotificationConfig),
+                    Config = V03TypeConverter.ToV1TaskPushNotificationConfig(v03Config),
                 };
                 var v1Result = await handler.CreateTaskPushNotificationConfigAsync(v1Request, ct).ConfigureAwait(false);
                 var v03Result = new V03.TaskPushNotificationConfig
                 {
-                    TaskId = v1Result.TaskId,
-                    PushNotificationConfig = V03TypeConverter.ToV03PushNotificationConfig(v1Result.PushNotificationConfig),
+                    TaskId = v1Result.TaskId ?? string.Empty,
+                    PushNotificationConfig = V03TypeConverter.ToV03PushNotificationConfigFromTask(v1Result),
                 };
                 return MakeSuccessResult(rpcRequest.Id, v03Result, typeof(V03.TaskPushNotificationConfig));
             }
@@ -390,8 +389,8 @@ private static async Task<IResult> HandleSingleAsync(
                 var v1Result = await handler.GetTaskPushNotificationConfigAsync(v1Request, ct).ConfigureAwait(false);
                 var v03Result = new V03.TaskPushNotificationConfig
                 {
-                    TaskId = v1Result.TaskId,
-                    PushNotificationConfig = V03TypeConverter.ToV03PushNotificationConfig(v1Result.PushNotificationConfig),
+                    TaskId = v1Result.TaskId ?? string.Empty,
+                    PushNotificationConfig = V03TypeConverter.ToV03PushNotificationConfigFromTask(v1Result),
                 };
                 return MakeSuccessResult(rpcRequest.Id, v03Result, typeof(V03.TaskPushNotificationConfig));
             }

src/A2A.V0_3Compat/V03TypeConverter.cs

@@ -194,9 +194,9 @@ internal static V03.MessageSendParams ToV03(A2A.SendMessageRequest request)
                 Blocking = !config.ReturnImmediately,
             };
 
-            if (config.PushNotificationConfig is { } pushConfig)
+            if (config.TaskPushNotificationConfig is { } pushConfig)
             {
-                result.Configuration.PushNotification = ToV03PushNotificationConfig(pushConfig);
+                result.Configuration.PushNotification = ToV03PushNotificationConfigFromTask(pushConfig);
             }
         }
 
@@ -424,6 +424,56 @@ internal static A2A.Artifact ToV1Artifact(V03.Artifact artifact) =>
 
     // ──── Push notification config conversion ────
 
+    /// <summary>Converts a v1.0 flat TaskPushNotificationConfig to a v0.3 PushNotificationConfig.</summary>
+    /// <param name="config">The v1.0 task push notification config to convert.</param>
+    /// <returns>The converted v0.3 push notification config.</returns>
+    internal static V03.PushNotificationConfig ToV03PushNotificationConfigFromTask(A2A.TaskPushNotificationConfig config)
+    {
+        var result = new V03.PushNotificationConfig
+        {
+            Url = config.Url,
+            Id = config.Id,
+            Token = config.Token,
+        };
+
+        if (config.Authentication is { } auth)
+        {
+            result.Authentication = new V03.PushNotificationAuthenticationInfo
+            {
+                Schemes = [auth.Scheme],
+                Credentials = auth.Credentials,
+            };
+        }
+
+        return result;
+    }
+
+    /// <summary>Converts a v0.3 PushNotificationConfig to a v1.0 flat TaskPushNotificationConfig.</summary>
+    /// <param name="config">The v0.3 push notification config to convert.</param>
+    /// <param name="taskId">The task identifier to include in the result.</param>
+    /// <returns>The converted v1.0 task push notification config.</returns>
+    internal static A2A.TaskPushNotificationConfig ToV1TaskPushNotificationConfigFromV03PushNotification(V03.PushNotificationConfig config, string taskId)
+    {
+        var result = new A2A.TaskPushNotificationConfig
+        {
+            Id = config.Id ?? string.Empty,
+            TaskId = taskId,
+            Url = config.Url,
+            Token = config.Token,
+        };
+
+        if (config.Authentication is { Schemes: { Count: > 0 } schemes })
+        {
+            result.Authentication = new A2A.AuthenticationInfo
+            {
+                Scheme = schemes[0],
+                Credentials = config.Authentication.Credentials,
+            };
+        }
+
+        return result;
+    }
+
     /// <summary>Converts a v1.0 push notification config to v0.3.</summary>
     /// <param name="config">The v1.0 config to convert.</param>
     /// <returns>The converted v0.3 push notification config.</returns>
@@ -460,31 +510,45 @@ internal static A2A.PushNotificationConfig ToV1PushNotificationConfig(V03.PushNo
             Token = config.Token,
         };
 
-        if (config.Authentication is { } auth && auth.Schemes.Count > 0)
+        if (config.Authentication is { Schemes: { Count: > 0 } schemes })
         {
             // v0.3 PushNotificationAuthenticationInfo.Schemes is a list; v1.0 AuthenticationInfo.Scheme
             // is a single string. Only the first scheme is preserved — multi-scheme configs lose data here.
             result.Authentication = new A2A.AuthenticationInfo
             {
-                Scheme = auth.Schemes[0],
-                Credentials = auth.Credentials,
+                Scheme = schemes[0],
+                Credentials = config.Authentication.Credentials,
             };
         }
 
         return result;
     }
 
-    /// <summary>Converts a v0.3 task push notification config to v1.0.</summary>
+    /// <summary>Converts a v0.3 task push notification config to v1.0 (flat structure).</summary>
     /// <param name="config">The v0.3 config to convert.</param>
     /// <returns>The converted v1.0 task push notification config.</returns>
-    internal static A2A.TaskPushNotificationConfig ToV1TaskPushNotificationConfig(V03.TaskPushNotificationConfig config) =>
-        new()
+    internal static A2A.TaskPushNotificationConfig ToV1TaskPushNotificationConfig(V03.TaskPushNotificationConfig config)
+    {
+        var result = new A2A.TaskPushNotificationConfig
         {
             Id = config.PushNotificationConfig.Id ?? string.Empty,
             TaskId = config.TaskId,
-            PushNotificationConfig = ToV1PushNotificationConfig(config.PushNotificationConfig),
+            Url = config.PushNotificationConfig.Url,
+            Token = config.PushNotificationConfig.Token,
         };
 
+        if (config.PushNotificationConfig.Authentication is { Schemes: { Count: > 0 } schemes })
+        {
+            result.Authentication = new A2A.AuthenticationInfo
+            {
+                Scheme = schemes[0],
+                Credentials = config.PushNotificationConfig.Authentication.Credentials,
+            };
+        }
+
+        return result;
+    }
+
     // ──── v0.3 request params → v1.0 request types (server-side compat) ────
 
     /// <summary>Converts v0.3 message send params to a v1.0 send message request.</summary>
@@ -498,8 +562,8 @@ internal static A2A.SendMessageRequest ToV1SendMessageRequest(V03.MessageSendPar
                 AcceptedOutputModes = cfg.AcceptedOutputModes,
                 HistoryLength = cfg.HistoryLength,
                 ReturnImmediately = !cfg.Blocking,
-                PushNotificationConfig = cfg.PushNotification is { } pn
-                    ? ToV1PushNotificationConfig(pn)
+                TaskPushNotificationConfig = cfg.PushNotification is { } pn
+                    ? ToV1TaskPushNotificationConfigFromV03PushNotification(pn, p.Message.TaskId ?? string.Empty)
                     : null,
             } : null,
             Metadata = p.Metadata,

src/A2A/Client/A2AHttpJsonClient.cs

@@ -104,8 +104,10 @@ public async IAsyncEnumerable<StreamResponse> SubscribeToTaskAsync(SubscribeToTa
     public async Task<TaskPushNotificationConfig> CreateTaskPushNotificationConfigAsync(
         CreateTaskPushNotificationConfigRequest request, CancellationToken cancellationToken = default)
     {
-        return await PostJsonAsync<PushNotificationConfig, TaskPushNotificationConfig>(
-            $"/tasks/{Uri.EscapeDataString(request.TaskId)}/pushNotificationConfigs",
+        ArgumentException.ThrowIfNullOrEmpty(request.Config.TaskId, "request.Config.TaskId");
+
+        return await PostJsonAsync<TaskPushNotificationConfig, TaskPushNotificationConfig>(
+            $"/tasks/{Uri.EscapeDataString(request.Config.TaskId)}/pushNotificationConfigs",
             request.Config, "CreateTaskPushNotificationConfig", cancellationToken).ConfigureAwait(false);
     }
 

src/A2A/Models/CreateTaskPushNotificationConfigRequest.cs

@@ -5,18 +5,7 @@ namespace A2A;
 /// <summary>Represents a request to create a push notification configuration.</summary>
 public sealed class CreateTaskPushNotificationConfigRequest
 {
-    /// <summary>Gets or sets the tenant identifier.</summary>
-    public string? Tenant { get; set; }
-
-    /// <summary>Gets or sets the task identifier.</summary>
-    [JsonRequired]
-    public string TaskId { get; set; } = string.Empty;
-
-    /// <summary>Unique identifier for the configuration.</summary>
-    [JsonRequired]
-    public string ConfigId { get; set; } = string.Empty;
-
-    /// <summary>Gets or sets the push notification configuration.</summary>
+    /// <summary>Gets or sets the push notification configuration to create.</summary>
     [JsonRequired]
-    public PushNotificationConfig Config { get; set; } = new();
+    public TaskPushNotificationConfig Config { get; set; } = new();
 }

src/A2A/Models/PushNotificationConfig.cs

@@ -2,7 +2,11 @@ namespace A2A;
 
 using System.Text.Json.Serialization;
 
-/// <summary>Represents a push notification configuration.</summary>
+/// <summary>Represents a push notification configuration (v0.3 shape).</summary>
+/// <remarks>
+/// In v1.0, the flat <see cref="TaskPushNotificationConfig"/> is preferred.
+/// This class is retained for backward compatibility with v0.3 and the HTTP+JSON endpoints.
+/// </remarks>
 public sealed class PushNotificationConfig
 {
     /// <summary>Unique identifier for the push notification configuration.</summary>

src/A2A/Models/SendMessageConfiguration.cs

@@ -8,8 +8,8 @@ public sealed class SendMessageConfiguration
     /// <summary>Gets or sets the accepted output modes.</summary>
     public List<string>? AcceptedOutputModes { get; set; }
 
-    /// <summary>Gets or sets the push notification configuration.</summary>
-    public PushNotificationConfig? PushNotificationConfig { get; set; }
+    /// <summary>Gets or sets the push notification configuration for this task.</summary>
+    public TaskPushNotificationConfig? TaskPushNotificationConfig { get; set; }
 
     /// <summary>Gets or sets the history length to include.</summary>
     public int? HistoryLength { get; set; }

src/A2A/Models/TaskPushNotificationConfig.cs

@@ -2,20 +2,24 @@ namespace A2A;
 
 using System.Text.Json.Serialization;
 
-/// <summary>Represents a task-specific push notification configuration.</summary>
+/// <summary>Represents a task-specific push notification configuration matching the v1 spec's flat structure.</summary>
 public sealed class TaskPushNotificationConfig
 {
     /// <summary>Gets or sets the configuration identifier.</summary>
-    [JsonRequired]
-    public string Id { get; set; } = string.Empty;
+    public string? Id { get; set; }
 
     /// <summary>Gets or sets the task identifier.</summary>
-    [JsonRequired]
-    public string TaskId { get; set; } = string.Empty;
+    public string? TaskId { get; set; }
 
-    /// <summary>Gets or sets the push notification configuration.</summary>
+    /// <summary>Gets or sets the URL for push notifications.</summary>
     [JsonRequired]
-    public PushNotificationConfig PushNotificationConfig { get; set; } = new();
+    public string Url { get; set; } = string.Empty;
+
+    /// <summary>Gets or sets the token for push notifications.</summary>
+    public string? Token { get; set; }
+
+    /// <summary>Gets or sets the authentication information.</summary>
+    public AuthenticationInfo? Authentication { get; set; }
 
     /// <summary>Gets or sets the tenant identifier.</summary>
     public string? Tenant { get; set; }

tests/A2A.AspNetCore.UnitTests/ClientTests.cs

@@ -100,14 +100,11 @@ public async Task TestCreatePushNotificationConfig()
             {
                 Id = "response-config-id",
                 TaskId = "test-task",
-                PushNotificationConfig = new PushNotificationConfig
+                Url = "http://example.org/notify",
+                Token = "test-token",
+                Authentication = new AuthenticationInfo
                 {
-                    Url = "http://example.org/notify",
-                    Token = "test-token",
-                    Authentication = new AuthenticationInfo
-                    {
-                        Scheme = "Bearer"
-                    }
+                    Scheme = "Bearer"
                 }
             };
 
@@ -120,9 +117,10 @@ public async Task TestCreatePushNotificationConfig()
 
         var createRequest = new CreateTaskPushNotificationConfigRequest
         {
-            TaskId = "test-task",
-            Config = new PushNotificationConfig()
+            Config = new TaskPushNotificationConfig()
             {
+                Id = "cfg-1",
+                TaskId = "test-task",
                 Url = "http://example.org/notify",
                 Token = "test-token",
                 Authentication = new AuthenticationInfo()

tests/A2A.UnitTests/Client/A2AClientTests.cs

@@ -33,7 +33,7 @@ public async Task SendMessageAsync_MapsRequestParamsCorrectly()
             Configuration = new SendMessageConfiguration
             {
                 AcceptedOutputModes = ["mode1"],
-                PushNotificationConfig = new PushNotificationConfig { Url = "http://push" },
+                TaskPushNotificationConfig = new TaskPushNotificationConfig { Id = "cfg-1", TaskId = "t-1", Url = "http://push" },
                 HistoryLength = 5,
                 ReturnImmediately = true
             },
@@ -339,11 +339,11 @@ public async Task CreatePushNotificationConfigAsync_SendsCorrectMethod()
         string? capturedBody = null;
 
         var sut = CreateA2AClient(
-            new TaskPushNotificationConfig { Id = "cfg-1", TaskId = "t-1", PushNotificationConfig = new PushNotificationConfig { Url = "http://push" } },
+            new TaskPushNotificationConfig { Id = "cfg-1", TaskId = "t-1", Url = "http://push" },
             req => capturedBody = req.Content!.ReadAsStringAsync().GetAwaiter().GetResult());
 
         // Act
-        await sut.CreateTaskPushNotificationConfigAsync(new CreateTaskPushNotificationConfigRequest { TaskId = "t-1", ConfigId = "cfg-1", Config = new PushNotificationConfig { Url = "http://push" } });
+        await sut.CreateTaskPushNotificationConfigAsync(new CreateTaskPushNotificationConfigRequest { Config = new TaskPushNotificationConfig { Id = "cfg-1", TaskId = "t-1", Url = "http://push" } });
 
         // Assert
         Assert.NotNull(capturedBody);

tests/A2A.UnitTests/Client/A2AHttpJsonClientTests.cs

@@ -193,16 +193,14 @@ public async Task CreateTaskPushNotificationConfigAsync_PostsCorrectBody()
         {
             Id = "cfg-1",
             TaskId = "t-1",
-            PushNotificationConfig = new PushNotificationConfig { Url = "http://callback" }
+            Url = "http://callback"
         };
 
         var sut = CreateClient(expected, req => captured = req);
 
         await sut.CreateTaskPushNotificationConfigAsync(new CreateTaskPushNotificationConfigRequest
         {
-            TaskId = "t-1",
-            ConfigId = "cfg-1",
-            Config = new PushNotificationConfig { Url = "http://callback" }
+            Config = new TaskPushNotificationConfig { Id = "cfg-1", TaskId = "t-1", Url = "http://callback" }
         });
 
         Assert.NotNull(captured);
@@ -218,7 +216,7 @@ public async Task GetTaskPushNotificationConfigAsync_UsesCorrectGetPath()
         {
             Id = "cfg-1",
             TaskId = "t-1",
-            PushNotificationConfig = new PushNotificationConfig { Url = "http://callback" }
+            Url = "http://callback"
         };
 
         var sut = CreateClient(expected, req => captured = req);
@@ -556,8 +554,7 @@ public async Task ErrorInfo_PushNotificationNotSupported_DistinguishesFrom400()
         var ex = await Assert.ThrowsAsync<A2AException>(() =>
             sut.CreateTaskPushNotificationConfigAsync(new CreateTaskPushNotificationConfigRequest
             {
-                TaskId = "t-1",
-                Config = new PushNotificationConfig { Url = "http://callback" }
+                Config = new TaskPushNotificationConfig { Id = "cfg-1", TaskId = "t-1", Url = "http://callback" }
             }));
 
         Assert.Equal(A2AErrorCode.PushNotificationNotSupported, ex.ErrorCode);