Connect VS Code / GitHub Copilot to StackJack

GitHub Copilot in VS Code supports remote MCP servers natively (MCP is the Model Context Protocol, the open standard AI tools use to call external tools). VS Code 1.101 and later signs in automatically the first time the server needs auth — no headers required.

Prerequisites

• VS Code 1.101 or later (this release added MCP authentication with automatic client registration).
• A GitHub Copilot subscription with Copilot Chat.
• A StackJack account that is a member of your workspace. Any team member can connect — no admin-created credentials needed for the sign-in path.
• Your StackJack MCP endpoint URL: https://mcp.stackjack.io/mcp.

Connect with sign-in (recommended)

1. Open the Command Palette and run MCP: Add Server → choose HTTP.
2. Paste the URL https://mcp.stackjack.io/mcp and confirm.
3. Start the server — VS Code opens a browser to sign in. Use the same email, password, and MFA you use for the StackJack Portal.
4. In Copilot Chat, switch to Agent mode to use your StackJack tools.

Alternatively, add this minimal .vscode/mcp.json (no headers) and start the server from the editor:

{
  "servers": {
    "stackjack": {
      "type": "http",
      "url": "https://mcp.stackjack.io/mcp"
    }
  }
}

Manual credentials (fallback)

An owner, co-owner, or Administrator creates an MCP client in the portal first (see Managing MCP credentials).

With a secure credential prompt — VS Code asks for the base64 value (echo -n "CLIENT_ID:CLIENT_SECRET" | base64) on first use and stores it as a secret:

{
  "inputs": [
    {
      "type": "promptString",
      "id": "stackjack-credentials",
      "description": "StackJack credentials (base64 of client_id:client_secret)",
      "password": true
    }
  ],
  "servers": {
    "stackjack": {
      "type": "http",
      "url": "https://mcp.stackjack.io/mcp",
      "headers": {
        "Authorization": "Basic ${input:stackjack-credentials}"
      }
    }
  }
}

Or hardcoded (simpler, but the credential is stored in plaintext):

{
  "servers": {
    "stackjack": {
      "type": "http",
      "url": "https://mcp.stackjack.io/mcp",
      "headers": {
        "Authorization": "Basic <BASE64_OF_CLIENT_ID:CLIENT_SECRET>"
      }
    }
  }
}

Tool limits

Copilot enforces a hard cap: a chat request can have a maximum of 128 tools enabled at a time, counting all MCP servers and built-in tools together. StackJack can expose hundreds of tools depending on your connectors and plan, so you will likely hit this. Ways to stay in range:

• Best long-term fix: catalog mode. Switch StackJack to compact (or minimal) mode so it serves a small tool list and Copilot discovers the rest on demand — this keeps you under 128 without hiding any tool, and every permission still applies. An admin must first enable catalog modes for your organization on Endpoints; until then StackJack serves the full tool list. See Choosing tools for each client and managing harness tool limits.
• Use Copilot Chat's Configure Tools picker to enable only the tools you need for the task.
• Since VS Code 1.103, Copilot can automatically group excess tools into expandable "virtual tools" when you exceed the threshold (controlled by the github.copilot.chat.virtualTools.threshold setting), so an over-limit list degrades gracefully instead of failing.
• Alternatively, connect through an MCP client with a restricted tool selection, or create several narrow clients for distinct workflows — see Choosing tools for each client.

Troubleshooting

• No sign-in prompt appears — check your VS Code version is 1.101+; older versions cannot register with StackJack automatically.
• Sign-in says no account was found — sign up in the portal first, or ask your team admin for an invite.
• For anything else, see Connection troubleshooting.