Add oauth section to mcp.json to allow overriding of client id

[TylerLeonhardt]

More properties (like client secret) can come later... but this is the foundation, which is a lot of plumbing...

ref #257415

So an MCP Config now can have:

		"my-mcp-server-43a791b0": {
			"url": "<url>",
			"type": "http",
			"oauth": {
				"clientId": "<guid>"
			}
		}

aligns with what Claude Code does: https://code.claude.com/docs/en/mcp#claude-mcp-add-json

[Copilot]

Pull request overview

Adds an oauth block to MCP HTTP server configuration to enable overriding the OAuth client ID used during authentication, plumbing that override through the MCP launch model into dynamic authentication provider/session acquisition.

Changes:

• Extend mcp.json HTTP server schema and MCP launch/types to carry optional oauth.clientId.
• Thread clientId through MCP auth token acquisition into the authentication service’s dynamic provider creation and session lookups.
• Teach microsoft-authentication (MSAL) provider to honor an explicit clientId override via ScopeData.

Show a summary per file

File	Description
src/vscode-dts/vscode.proposed.authIssuers.d.ts	Adds clientId?: string to proposed auth-issuer session option shapes.
src/vs/workbench/services/authentication/common/authentication.ts	Extends dynamic auth provider creation APIs to accept optional clientId.
src/vs/workbench/services/authentication/browser/authenticationService.ts	Forwards optional clientId into the host delegate’s dynamic provider creation.
src/vs/workbench/contrib/mcp/common/mcpTypes.ts	Adds oauth to HTTP launch types and serialization.
src/vs/workbench/contrib/mcp/common/mcpConfiguration.ts	Adds oauth section to the mcp.json schema for HTTP servers.
src/vs/workbench/contrib/mcp/common/discovery/pluginMcpDiscovery.ts	Maps discovered plugin MCP HTTP configs to include oauth.
src/vs/workbench/contrib/mcp/common/discovery/installedMcpServersDiscovery.ts	Maps installed MCP HTTP configs to include oauth.
src/vs/workbench/api/common/extHostMcp.ts	Passes configured oauth.clientId into MCP auth token requests.
src/vs/workbench/api/common/extHost.protocol.ts	Extends MCP auth RPC option/details types with optional clientId.
src/vs/workbench/api/browser/mainThreadMcp.ts	Forwards clientId into auth session retrieval and dynamic provider creation.
src/vs/workbench/api/browser/mainThreadAuthentication.ts	Allows overriding clientId during dynamic auth provider registration (skips stored secret).
src/vs/platform/mcp/common/mcpPlatformTypes.ts	Adds oauth to remote MCP server configuration types.
extensions/microsoft-authentication/src/node/authProvider.ts	Threads clientId option into ScopeData for MSAL flows.
extensions/microsoft-authentication/src/common/scopeData.ts	Adds constructor support for explicit clientId override.

Copilot's findings

• Files reviewed: 13/14 changed files
• Comments generated: 5