MCP `resources/read` doesn't support multiple Resources in result

[pattobrien]

Steps to Reproduce:

1. Create a MCP Server that has a Resource that returns multiple resources (valid response, see annotation in MCP docs)

server.setRequestHandler(
  ListResourcesRequestSchema,
  async () => {
    return {
      resources: [
        {
          name: "System Prompts",
          description: "Directory for system prompts in the current workspace.",
          uri: "file://prompts/",
        },
      ],
    } satisfies ListResourcesResult;
  },
);
server.setRequestHandler(
  ReadResourceRequestSchema,
  async (request) => {
    return {
      contents: [
        {
          uri: "file://prompts/prompt-1.md",
          text: "foo1",
        },
        {
          uri: "file://prompts/prompt-2.md",
          text: "foo2",
        },
      ],
    } satisfies ReadResourceResult;
  },
);

2. In VSCode: Command Palette > "MCP: Browse Resources" > "System Prompts"

Expected Result

Each Resource returned in the ReadResourceResult object could be shown in perhaps one of the following two ways:

a) both files should open as tabs in the editor (similar to how Claude Desktop handles this) OR
b) another dialog should appear showing each resource, with an ability to multi-select each one individually

Observed Result

No files are displayed, with the error "The file is not displayed in the text editor because it is a directory."

VSCode info

Does this issue occur when all extensions are disabled?: Yes

Version: 1.101.0
Commit: dfaf441
Date: 2025-06-11T15:00:50.123Z (6 days ago)
Electron: 35.5.1
ElectronBuildId: 11727614
Chromium: 134.0.6998.205
Node.js: 22.15.1
V8: 13.4.114.21-electron.0
OS: Darwin arm64 24.5.0