Visual Studio MCP server: add Sume's hosted MCP in .mcp.json

Visual Studio 2022 version 17.14 and Visual Studio 2026 let GitHub Copilot agent mode use tools from MCP servers. To add Sume's hosted MCP server, put "servers": { "sume": { "url": "https://mcp.sume.com/mcp" } } in an .mcp.json file that Visual Studio reads, such as %USERPROFILE%\.mcp.json, save it, and use the file's CodeLens (Authentication Required or Manage Authentication) to sign in to Sume in your browser.

This is Visual Studio for Windows; for VS Code, see VS Code remote MCP server. Visual Studio's side comes from Microsoft's Use MCP servers in Visual Studio; Sume's side comes from MCP quickstart, MCP OAuth and API keys, and MCP tools and gates, all read on 2026-09-27. Sume has no official Visual Studio integration, and Sume's basics page says hosted MCP still works but is not part of the primary path today.

Where does Visual Studio look for MCP servers?

Visual Studio reads MCP server configurations from these files, in this order. Some locations require .mcp.json and others mcp.json. When you save a file with valid syntax, the Copilot agent restarts and reloads the configured servers.

You can also add a server from chat: switch the chat pane to Agent mode, select Tools, select the plus (+) button, choose Add custom MCP server, and enter the name and URL in the Add MCP server dialog.

What goes in the Sume entry?

Only the URL, in the same shape as Microsoft's remote-server example. The entry holds no secret, so <SOLUTIONDIR>\.mcp.json can go into source control for a team. Edit it in Visual Studio so its JSON schema is applied:

{
  "servers": {
    "sume": {
      "url": "https://mcp.sume.com/mcp"
    }
  }
}

How do I sign in to Sume from Visual Studio?

Visual Studio supports authentication for remote servers with any OAuth provider, following the MCP authorization specification. After saving, select Authentication Required, or Manage Authentication, in the file's CodeLens, and finish in the browser pop-up. If no CodeLens appears, turn it on in Tools > Options > Text Editor > CodeLens.

On Sume's side, the client discovers protected-resource metadata from the MCP endpoint and sends you to https://mcp.sume.com/oauth/authorize. Consent happens on mcp.sume.com: Read is locked on and the Write toggle is off by default. Sume's current server advertises dynamic client registration and PKCE with S256, and its access tokens last one hour with no refresh token, so plan on signing in again after an hour. Sume's MCP OAuth flow covers each step.

With Write off, the session is mcp:read: read tools such as jobs_list and catalog_list work, while write and paid tools such as jobs_cancel and generate_image return insufficient_scope. Turn Write on at consent to add mcp:write; there is no mcp:paid scope.

Will Copilot ask before it calls a Sume tool?

Yes. A new server's tools are disabled by default, and you enable the ones you want. When Copilot invokes a tool, it asks for confirmation, and the Allow dropdown can confirm that tool automatically for the current session, the current solution, or all future invocations; you can reset those choices in Tools > Options. When a server sends a tool-list-changed notification, Visual Studio resets prior acceptances and permissions on its tools.

Leave Sume's paid tools on per-call confirmation. Each paid call needs an idempotency_key, dry_run=true previews admission and cost without submitting the job, and max_spend_usd caps a call only when it is sent.

What can stop the server from connecting?

• An organization allow list: when one is configured through GitHub, Visual Studio connects only to approved MCP servers and shows an error for any other.
• The GitHub policy for agent mode and MCP: if an administrator turns it off, users under that subscription can't use agent mode or connect to MCP servers.
• A changed server: from Visual Studio 2026 version 18.7, a trust dialog asks again when a server's configuration or capabilities change, and Reject stops it from starting.
• Once connected, ask Copilot to call mcp_health, which confirms the endpoint, auth source, and safety posture, then tools_list. Sume MCP tools list groups every hosted tool by read, write, and paid.