sdk: Expose githubMcpToolConfig across languages

dotnet/src/Client.cs

@@ -1196,6 +1196,7 @@ public async Task<CopilotSession> CreateSessionAsync(SessionConfig config, Cance
                 ToolFilterPrecedence: toolFilter.ToolFilterPrecedence,
                 ExpAssignments: config.ExpAssignments,
                 EnableManagedSettings: config.EnableManagedSettings,
+                GitHubMcpToolConfig: config.GitHubMcpToolConfig,
                 EnableGitHubTelemetryForwarding: _options.OnGitHubTelemetry != null ? true : null);
 
             var rpcTimestamp = Stopwatch.GetTimestamp();
@@ -1410,6 +1411,7 @@ public async Task<CopilotSession> ResumeSessionAsync(string sessionId, ResumeSes
                 ToolFilterPrecedence: toolFilter.ToolFilterPrecedence,
                 ExpAssignments: config.ExpAssignments,
                 EnableManagedSettings: config.EnableManagedSettings,
+                GitHubMcpToolConfig: config.GitHubMcpToolConfig,
                 EnableGitHubTelemetryForwarding: _options.OnGitHubTelemetry != null ? true : null);
 
             var rpcTimestamp = Stopwatch.GetTimestamp();
@@ -2762,7 +2764,8 @@ internal record CreateSessionRequest(
         OptionsUpdateToolFilterPrecedence? ToolFilterPrecedence = null,
         [property: JsonPropertyName("expAssignments")] CopilotExpAssignmentResponse? ExpAssignments = null,
         [property: JsonPropertyName("enableManagedSettings")] bool? EnableManagedSettings = null,
-        bool? EnableGitHubTelemetryForwarding = null);
+        bool? EnableGitHubTelemetryForwarding = null,
+        [property: JsonPropertyName("githubMcpToolConfig")] GitHubMcpToolConfig? GitHubMcpToolConfig = null);
 #pragma warning restore GHCP001
 
     internal record ToolDefinition(
@@ -2868,7 +2871,8 @@ internal record ResumeSessionRequest(
         OptionsUpdateToolFilterPrecedence? ToolFilterPrecedence = null,
         [property: JsonPropertyName("expAssignments")] CopilotExpAssignmentResponse? ExpAssignments = null,
         [property: JsonPropertyName("enableManagedSettings")] bool? EnableManagedSettings = null,
-        bool? EnableGitHubTelemetryForwarding = null);
+        bool? EnableGitHubTelemetryForwarding = null,
+        [property: JsonPropertyName("githubMcpToolConfig")] GitHubMcpToolConfig? GitHubMcpToolConfig = null);
 #pragma warning restore GHCP001
 
     internal record ResumeSessionResponse(

dotnet/src/Types.cs

@@ -2957,6 +2957,36 @@ public sealed class CopilotExpAssignmentResponse
     public string AssignmentContext { get; set; } = string.Empty;
 }
 
+/// <summary>
+/// Configuration for the built-in GitHub MCP server.
+/// </summary>
+public sealed class GitHubMcpToolConfig
+{
+    /// <summary>Enables all GitHub MCP tools.</summary>
+    [JsonPropertyName("enableAllTools")]
+    public bool? EnableAllTools { get; set; }
+
+    /// <summary>Additional GitHub MCP toolsets to enable.</summary>
+    [JsonPropertyName("additionalToolsets")]
+    public IList<string>? AdditionalToolsets { get; set; }
+
+    /// <summary>Additional GitHub MCP tools to enable.</summary>
+    [JsonPropertyName("additionalTools")]
+    public IList<string>? AdditionalTools { get; set; }
+
+    /// <summary>Enables GitHub MCP insiders-mode tools.</summary>
+    [JsonPropertyName("enableInsidersMode")]
+    public bool? EnableInsidersMode { get; set; }
+
+    /// <summary>
+    /// Disables form deferral for GitHub MCP tools. This only applies to the
+    /// built-in GitHub MCP server and only has an effect when MCP Apps and
+    /// form-backed GitHub tools are enabled.
+    /// </summary>
+    [JsonPropertyName("disableFormDeferral")]
+    public bool? DisableFormDeferral { get; set; }
+}
+
 /// <summary>
 /// Shared configuration properties for creating or resuming a Copilot session.
 /// Use <see cref="SessionConfig"/> when creating a new session, or
@@ -2994,6 +3024,20 @@ protected SessionConfigBase(SessionConfigBase? other)
         EnableSessionStore = other.EnableSessionStore;
         EnableSkills = other.EnableSkills;
         EnableMcpApps = other.EnableMcpApps;
+        GitHubMcpToolConfig = other.GitHubMcpToolConfig is null
+            ? null
+            : new GitHubMcpToolConfig
+            {
+                EnableAllTools = other.GitHubMcpToolConfig.EnableAllTools,
+                AdditionalToolsets = other.GitHubMcpToolConfig.AdditionalToolsets is not null
+                    ? [.. other.GitHubMcpToolConfig.AdditionalToolsets]
+                    : null,
+                AdditionalTools = other.GitHubMcpToolConfig.AdditionalTools is not null
+                    ? [.. other.GitHubMcpToolConfig.AdditionalTools]
+                    : null,
+                EnableInsidersMode = other.GitHubMcpToolConfig.EnableInsidersMode,
+                DisableFormDeferral = other.GitHubMcpToolConfig.DisableFormDeferral,
+            };
         ExcludedBuiltInAgents = other.ExcludedBuiltInAgents is not null ? [.. other.ExcludedBuiltInAgents] : null;
         ExcludedTools = other.ExcludedTools is not null ? [.. other.ExcludedTools] : null;
         Hooks = other.Hooks;
@@ -3309,6 +3353,13 @@ protected SessionConfigBase(SessionConfigBase? other)
     [Experimental(Diagnostics.Experimental)]
     public bool EnableMcpApps { get; set; }
 
+    /// <summary>
+    /// Configuration for the built-in GitHub MCP server.
+    /// <c>DisableFormDeferral</c> only applies to that server and only has an
+    /// effect when MCP Apps and form-backed GitHub tools are enabled.
+    /// </summary>
+    public GitHubMcpToolConfig? GitHubMcpToolConfig { get; set; }
+
     /// <summary>Hook handlers for session lifecycle events.</summary>
     public SessionHooks? Hooks { get; set; }
 

dotnet/test/Unit/SerializationTests.cs

@@ -299,6 +299,51 @@ public void SessionRequests_OmitCapiOptions_WhenUnset()
         Assert.False(resumeDocument.RootElement.TryGetProperty("capi", out _));
     }
 
+    [Fact]
+    public void SessionRequests_CanSerializeGitHubMcpToolConfig_WithSdkOptions()
+    {
+        var options = GetSerializerOptions();
+        var githubConfig = new GitHubMcpToolConfig
+        {
+            EnableAllTools = true,
+            AdditionalToolsets = ["repos"],
+            AdditionalTools = ["get_issue"],
+            EnableInsidersMode = true,
+            DisableFormDeferral = true,
+        };
+
+        var createRequestType = GetNestedType(typeof(CopilotClient), "CreateSessionRequest");
+        var createRequest = CreateInternalRequest(
+            createRequestType,
+            ("GitHubMcpToolConfig", githubConfig));
+        using var createDocument = JsonDocument.Parse(JsonSerializer.Serialize(createRequest, createRequestType, options));
+        var createConfig = createDocument.RootElement.GetProperty("githubMcpToolConfig");
+        Assert.True(createConfig.GetProperty("enableAllTools").GetBoolean());
+        Assert.Equal("repos", createConfig.GetProperty("additionalToolsets")[0].GetString());
+        Assert.True(createConfig.GetProperty("disableFormDeferral").GetBoolean());
+
+        var resumeRequestType = GetNestedType(typeof(CopilotClient), "ResumeSessionRequest");
+        var resumeRequest = CreateInternalRequest(
+            resumeRequestType,
+            ("SessionId", "session-id"),
+            ("GitHubMcpToolConfig", githubConfig));
+        using var resumeDocument = JsonDocument.Parse(JsonSerializer.Serialize(resumeRequest, resumeRequestType, options));
+        Assert.True(resumeDocument.RootElement.TryGetProperty("githubMcpToolConfig", out _));
+    }
+
+    [Fact]
+    public void SessionRequests_OmitGitHubMcpToolConfig_WhenUnset()
+    {
+        var options = GetSerializerOptions();
+        foreach (var requestName in new[] { "CreateSessionRequest", "ResumeSessionRequest" })
+        {
+            var requestType = GetNestedType(typeof(CopilotClient), requestName);
+            var request = CreateInternalRequest(requestType, ("SessionId", "session-id"));
+            using var document = JsonDocument.Parse(JsonSerializer.Serialize(request, requestType, options));
+            Assert.False(document.RootElement.TryGetProperty("githubMcpToolConfig", out _));
+        }
+    }
+
     [Fact]
     public void SessionRequests_CanSerializeReasoningSummary_WithSdkOptions()
     {

go/client.go

@@ -848,6 +848,7 @@ func (c *Client) CreateSession(ctx context.Context, config *SessionConfig) (*Ses
 	if config.EnableMCPApps {
 		req.RequestMCPApps = Bool(true)
 	}
+	req.GitHubMCPToolConfig = config.GitHubMCPToolConfig
 
 	if config.Streaming != nil {
 		req.Streaming = config.Streaming
@@ -1220,6 +1221,7 @@ func (c *Client) ResumeSessionWithOptions(ctx context.Context, sessionID string,
 	if config.EnableMCPApps {
 		req.RequestMCPApps = Bool(true)
 	}
+	req.GitHubMCPToolConfig = config.GitHubMCPToolConfig
 
 	traceparent, tracestate := getTraceContext(ctx)
 	req.Traceparent = traceparent

go/client_test.go

@@ -2363,6 +2363,68 @@ func TestResumeSessionRequest_RequestMCPApps(t *testing.T) {
 	})
 }
 
+func TestSessionRequests_GitHubMCPToolConfig(t *testing.T) {
+	config := &GitHubMCPToolConfig{
+		EnableAllTools:      Bool(true),
+		AdditionalToolsets:  []string{"repos"},
+		AdditionalTools:     []string{"get_issue"},
+		EnableInsidersMode:  Bool(true),
+		DisableFormDeferral: Bool(true),
+	}
+	expected := map[string]any{
+		"enableAllTools":      true,
+		"additionalToolsets":  []any{"repos"},
+		"additionalTools":     []any{"get_issue"},
+		"enableInsidersMode":  true,
+		"disableFormDeferral": true,
+	}
+
+	t.Run("create", func(t *testing.T) {
+		data, err := json.Marshal(createSessionRequest{GitHubMCPToolConfig: config})
+		if err != nil {
+			t.Fatalf("Failed to marshal: %v", err)
+		}
+		var payload map[string]any
+		if err := json.Unmarshal(data, &payload); err != nil {
+			t.Fatalf("Failed to unmarshal: %v", err)
+		}
+		if !reflect.DeepEqual(payload["githubMcpToolConfig"], expected) {
+			t.Fatalf("Unexpected githubMcpToolConfig: %#v", payload["githubMcpToolConfig"])
+		}
+	})
+
+	t.Run("resume", func(t *testing.T) {
+		data, err := json.Marshal(resumeSessionRequest{
+			SessionID:           "s1",
+			GitHubMCPToolConfig: config,
+		})
+		if err != nil {
+			t.Fatalf("Failed to marshal: %v", err)
+		}
+		var payload map[string]any
+		if err := json.Unmarshal(data, &payload); err != nil {
+			t.Fatalf("Failed to unmarshal: %v", err)
+		}
+		if !reflect.DeepEqual(payload["githubMcpToolConfig"], expected) {
+			t.Fatalf("Unexpected githubMcpToolConfig: %#v", payload["githubMcpToolConfig"])
+		}
+	})
+
+	t.Run("unset is omitted", func(t *testing.T) {
+		data, err := json.Marshal(createSessionRequest{})
+		if err != nil {
+			t.Fatalf("Failed to marshal: %v", err)
+		}
+		var payload map[string]any
+		if err := json.Unmarshal(data, &payload); err != nil {
+			t.Fatalf("Failed to unmarshal: %v", err)
+		}
+		if _, ok := payload["githubMcpToolConfig"]; ok {
+			t.Fatal("Expected githubMcpToolConfig to be omitted")
+		}
+	})
+}
+
 func TestResumeSessionRequest_ModeCallbackFlags(t *testing.T) {
 	req := resumeSessionRequest{
 		SessionID:             "s1",

go/types.go

@@ -1140,6 +1140,18 @@ func (e ExpConfigEntry) MarshalJSON() ([]byte, error) {
 	return json.Marshal(w)
 }
 
+// GitHubMCPToolConfig configures the built-in GitHub MCP server.
+//
+// DisableFormDeferral only applies to the built-in GitHub MCP server and only
+// has an effect when MCP Apps and form-backed GitHub tools are enabled.
+type GitHubMCPToolConfig struct {
+	EnableAllTools      *bool    `json:"enableAllTools,omitempty"`
+	AdditionalToolsets  []string `json:"additionalToolsets,omitempty"`
+	AdditionalTools     []string `json:"additionalTools,omitempty"`
+	EnableInsidersMode  *bool    `json:"enableInsidersMode,omitempty"`
+	DisableFormDeferral *bool    `json:"disableFormDeferral,omitempty"`
+}
+
 // SessionConfig configures a new session
 type SessionConfig struct {
 	// SessionID is an optional custom session ID
@@ -1379,6 +1391,10 @@ type SessionConfig struct {
 	// cause MCP servers to register UI-enabled tool variants the consumer cannot
 	// display.
 	EnableMCPApps bool
+	// GitHubMCPToolConfig configures the built-in GitHub MCP server.
+	// DisableFormDeferral only applies to that server and only has an effect
+	// when MCP Apps and form-backed GitHub tools are enabled.
+	GitHubMCPToolConfig *GitHubMCPToolConfig
 	// GitHubToken is an optional per-session GitHub token used for authentication.
 	// When provided, the session authenticates as the token's owner instead of
 	// using the global client-level auth.
@@ -1847,6 +1863,10 @@ type ResumeSessionConfig struct {
 	// Experimental: EnableMCPApps is part of an experimental wire-protocol
 	// surface (SEP-1865) and may change or be removed in a future release.
 	EnableMCPApps bool
+	// GitHubMCPToolConfig configures the built-in GitHub MCP server.
+	// DisableFormDeferral only applies to that server and only has an effect
+	// when MCP Apps and form-backed GitHub tools are enabled.
+	GitHubMCPToolConfig *GitHubMCPToolConfig
 	// Canvases declares canvases this session provides. Sent over the wire on
 	// `session.resume`. See SessionConfig.Canvases.
 	Canvases []CanvasDeclaration
@@ -2327,6 +2347,7 @@ type createSessionRequest struct {
 	Commands                           []wireCommand                          `json:"commands,omitempty"`
 	RequestElicitation                 *bool                                  `json:"requestElicitation,omitempty"`
 	RequestMCPApps                     *bool                                  `json:"requestMcpApps,omitempty"`
+	GitHubMCPToolConfig                *GitHubMCPToolConfig                   `json:"githubMcpToolConfig,omitempty"`
 	GitHubToken                        string                                 `json:"gitHubToken,omitempty"`
 	RemoteSession                      rpc.RemoteSessionMode                  `json:"remoteSession,omitempty"`
 	Cloud                              *CloudSessionOptions                   `json:"cloud,omitempty"`
@@ -2419,6 +2440,7 @@ type resumeSessionRequest struct {
 	Commands                           []wireCommand                          `json:"commands,omitempty"`
 	RequestElicitation                 *bool                                  `json:"requestElicitation,omitempty"`
 	RequestMCPApps                     *bool                                  `json:"requestMcpApps,omitempty"`
+	GitHubMCPToolConfig                *GitHubMCPToolConfig                   `json:"githubMcpToolConfig,omitempty"`
 	GitHubToken                        string                                 `json:"gitHubToken,omitempty"`
 	RemoteSession                      rpc.RemoteSessionMode                  `json:"remoteSession,omitempty"`
 	Canvases                           []CanvasDeclaration                    `json:"canvases,omitempty"`

java/src/main/java/com/github/copilot/SessionRequestBuilder.java

@@ -176,6 +176,7 @@ static CreateSessionRequest buildCreateRequest(SessionConfig config, String sess
         if (config.isEnableMcpApps()) {
             request.setRequestMcpApps(true);
         }
+        request.setGitHubMcpToolConfig(config.getGitHubMcpToolConfig());
         if (config.getOnExitPlanMode() != null) {
             request.setRequestExitPlanMode(true);
         }
@@ -300,6 +301,7 @@ static ResumeSessionRequest buildResumeRequest(String sessionId, ResumeSessionCo
         if (config.isEnableMcpApps()) {
             request.setRequestMcpApps(true);
         }
+        request.setGitHubMcpToolConfig(config.getGitHubMcpToolConfig());
         if (config.getOnExitPlanMode() != null) {
             request.setRequestExitPlanMode(true);
         }

java/src/main/java/com/github/copilot/rpc/CreateSessionRequest.java

@@ -193,6 +193,9 @@ public final class CreateSessionRequest {
     @JsonProperty("requestMcpApps")
     private Boolean requestMcpApps;
 
+    @JsonProperty("githubMcpToolConfig")
+    private GitHubMcpToolConfig githubMcpToolConfig;
+
     @JsonProperty("requestExitPlanMode")
     private Boolean requestExitPlanMode;
 
@@ -902,6 +905,16 @@ public void clearRequestMcpApps() {
         this.requestMcpApps = null;
     }
 
+    /** Gets the GitHub MCP tool configuration. @return the configuration */
+    public GitHubMcpToolConfig getGitHubMcpToolConfig() {
+        return githubMcpToolConfig;
+    }
+
+    /** Sets the GitHub MCP tool configuration. @param config the value */
+    public void setGitHubMcpToolConfig(GitHubMcpToolConfig config) {
+        this.githubMcpToolConfig = config;
+    }
+
     /** Gets the requestExitPlanMode flag. @return the flag */
     public Boolean getRequestExitPlanMode() {
         return requestExitPlanMode;