Add githubMcpServer.channel setting for MCP Insiders mode

package.json

@@ -3330,6 +3330,22 @@
 							"experimental"
 						]
 					},
+					"github.copilot.chat.githubMcpServer.channel": {
+						"type": "string",
+						"default": "stable",
+						"enum": [
+							"stable",
+							"insiders"
+						],
+						"enumDescriptions": [
+							"%github.copilot.config.githubMcpServer.channel.stable%",
+							"%github.copilot.config.githubMcpServer.channel.insiders%"
+						],
+						"markdownDescription": "%github.copilot.config.githubMcpServer.channel%",
+						"tags": [
+							"experimental"
+						]
+					},
 					"github.copilot.chat.switchAgent.enabled": {
 						"type": "boolean",
 						"default": false,

package.nls.json

@@ -469,6 +469,9 @@
 	"github.copilot.config.githubMcpServer.toolsets": "Specify toolsets to use from the GitHub MCP Server. [Learn more](https://aka.ms/vscode-gh-mcp-toolsets).",
 	"github.copilot.config.githubMcpServer.readonly": "Enable read-only mode for the GitHub MCP Server. When enabled, only read tools are available. [Learn more](https://aka.ms/vscode-gh-mcp-readonly).",
 	"github.copilot.config.githubMcpServer.lockdown": "Enable lockdown mode for the GitHub MCP Server. When enabled, hides public issue details created by users without push access. [Learn more](https://aka.ms/vscode-gh-mcp-lockdown).",
+	"github.copilot.config.githubMcpServer.channel": "Select the channel for the GitHub MCP Server. When set to Insiders, enables access to experimental features that may change or be removed based on community feedback. [Learn more](https://aka.ms/vscode-gh-mcp-channel).",
+	"github.copilot.config.githubMcpServer.channel.stable": "Use the stable version of the GitHub MCP Server.",
+	"github.copilot.config.githubMcpServer.channel.insiders": "Connect to the Insiders version of the GitHub MCP Server with experimental features.",
 	"copilot.tools.runSubagent.name": "Run Subagent",
 	"copilot.tools.runSubagent.description": "Runs a task within an isolated subagent context. Enables efficient organization of tasks and context window management.",
 	"copilot.tools.searchSubagent.name": "Search Subagent",

src/extension/githubMcp/common/githubMcpDefinitionProvider.ts

@@ -41,6 +41,11 @@ export class GitHubMcpDefinitionProvider implements McpServerDefinitionProvider<
 					logService.debug('GitHubMcpDefinitionProvider: Configuration change affects GitHub MCP lockdown mode.');
 					return true;
 				}
+				// If they change the channel
+				if (e.affectsConfiguration(ConfigKey.GitHubMcpChannel.fullyQualifiedId)) {
+					logService.debug('GitHubMcpDefinitionProvider: Configuration change affects GitHub MCP channel.');
+					return true;
+				}
 				// If they change to GHE or GitHub.com
 				if (e.affectsConfiguration(ConfigKey.Shared.AuthProvider.fullyQualifiedId)) {
 					logService.debug('GitHubMcpDefinitionProvider: Configuration change affects GitHub auth provider.');
@@ -82,6 +87,10 @@ export class GitHubMcpDefinitionProvider implements McpServerDefinitionProvider<
 		return this.configurationService.getConfig<boolean>(ConfigKey.GitHubMcpLockdown);
 	}
 
+	private get channel(): ConfigKey.GitHubMcpChannelValue {
+		return this.configurationService.getConfig<ConfigKey.GitHubMcpChannelValue>(ConfigKey.GitHubMcpChannel);
+	}
+
 	private get gheConfig(): string | undefined {
 		return this.configurationService.getNonExtensionConfig<string>(EnterpriseURLConfig);
 	}
@@ -101,6 +110,7 @@ export class GitHubMcpDefinitionProvider implements McpServerDefinitionProvider<
 		const toolsets = this.toolsets.sort().join(',');
 		const readonly = this.readonly;
 		const lockdown = this.lockdown;
+		const channel = this.channel;
 		const isSignedIn = !!this.authenticationService.permissiveGitHubSession;
 
 		const basics = providerId === AuthProviderId.GitHubEnterprise
@@ -124,6 +134,10 @@ export class GitHubMcpDefinitionProvider implements McpServerDefinitionProvider<
 				headers['X-MCP-Lockdown'] = 'true';
 				version += '|lockdown';
 			}
+			if (channel === 'insiders') {
+				headers['X-MCP-Insiders'] = 'true';
+				version += '|insiders';
+			}
 		} else {
 			version = 'signedout';
 		}

src/extension/githubMcp/test/node/githubMcpDefinitionProvider.spec.ts

@@ -82,6 +82,7 @@ describe('GitHubMcpDefinitionProvider', () => {
 		toolsets?: string[];
 		readonly?: boolean;
 		lockdown?: boolean;
+		channel?: ConfigKey.GitHubMcpChannelValue;
 		hasPermissiveToken?: boolean;
 	}): Promise<GitHubMcpDefinitionProvider> {
 		const serviceCollection = new TestingServiceCollection();
@@ -103,6 +104,9 @@ describe('GitHubMcpDefinitionProvider', () => {
 		if (configOverrides?.lockdown !== undefined) {
 			await configService.setConfig(ConfigKey.GitHubMcpLockdown, configOverrides.lockdown);
 		}
+		if (configOverrides?.channel !== undefined) {
+			await configService.setConfig(ConfigKey.GitHubMcpChannel, configOverrides.channel);
+		}
 
 		serviceCollection.define(IConfigurationService, configService);
 		serviceCollection.define(ICopilotTokenStore, new SyncDescriptor(CopilotTokenStore));
@@ -251,6 +255,38 @@ describe('GitHubMcpDefinitionProvider', () => {
 			expect(definitions[0].version).toBe('default|readonly|lockdown');
 		});
 
+		test('includes X-MCP-Insiders header when channel is insiders', async () => {
+			const insidersProvider = await createProvider({ channel: 'insiders' });
+
+			const definitions = insidersProvider.provideMcpServerDefinitions();
+
+			expect(definitions[0].headers['X-MCP-Insiders']).toBe('true');
+		});
+
+		test('does not include X-MCP-Insiders header when channel is stable', async () => {
+			const stableProvider = await createProvider({ channel: 'stable' });
+
+			const definitions = stableProvider.provideMcpServerDefinitions();
+
+			expect(definitions[0].headers['X-MCP-Insiders']).toBeUndefined();
+		});
+
+		test('version includes insiders flag when channel is insiders', async () => {
+			const insidersProvider = await createProvider({ channel: 'insiders' });
+
+			const definitions = insidersProvider.provideMcpServerDefinitions();
+
+			expect(definitions[0].version).toBe('default|insiders');
+		});
+
+		test('version includes all flags when readonly, lockdown, and insiders are set', async () => {
+			const allFlagsProvider = await createProvider({ readonly: true, lockdown: true, channel: 'insiders' });
+
+			const definitions = allFlagsProvider.provideMcpServerDefinitions();
+
+			expect(definitions[0].version).toBe('default|readonly|lockdown|insiders');
+		});
+
 		test('version is just toolsets when readonly and lockdown are false', async () => {
 			const toolsets = ['issues', 'pull_requests'];
 			const normalProvider = await createProvider({ toolsets, readonly: false, lockdown: false });
@@ -327,6 +363,14 @@ describe('GitHubMcpDefinitionProvider', () => {
 
 			await eventPromise;
 		});
+
+		test('fires when channel configuration changes', async () => {
+			const eventPromise = Event.toPromise(provider.onDidChangeMcpServerDefinitions);
+
+			await configService.setConfig(ConfigKey.GitHubMcpChannel, 'insiders');
+
+			await eventPromise;
+		});
 	});
 
 	describe('edge cases', () => {

src/platform/configuration/common/configurationService.ts

@@ -977,6 +977,8 @@ export namespace ConfigKey {
 	export const GitHubMcpToolsets = defineSetting<string[]>('chat.githubMcpServer.toolsets', ConfigType.Simple, ['default']);
 	export const GitHubMcpReadonly = defineSetting<boolean>('chat.githubMcpServer.readonly', ConfigType.Simple, false);
 	export const GitHubMcpLockdown = defineSetting<boolean>('chat.githubMcpServer.lockdown', ConfigType.Simple, false);
+	export type GitHubMcpChannelValue = 'stable' | 'insiders';
+	export const GitHubMcpChannel = defineSetting<GitHubMcpChannelValue>('chat.githubMcpServer.channel', ConfigType.Simple, 'stable');
 
 	export const GetSearchResultsViewSkill = defineSetting<boolean>('chat.getSearchViewResultsSkill.enabled', ConfigType.ExperimentBased, false);