Aspire MCP server via HTTP: how to get the API key when aspire CLI is detected?

[CharlieDigital]

Problem

I would like to standardize access to Aspire MCP across my team.

1. Not all developers have installed the aspire CLI, even if they are using Aspire.
2. Not all developers are using the same agent harness (Copilot, Claude Code, OpenCode, etc)

Therefore, I would like to use the HTTP interface to connect their agents to Aspire running locally.

Ideally, it is possible via launchSettings.json to set a common API key so that the .vscode/mcp.json (or other configuration files) can be standardized:

{
  "$schema": "https://json.schemastore.org/launchsettings.json",
  "profiles": {
    "http": {
      "commandName": "Project",
      "dotnetRunMessages": true,
      "launchBrowser": true,
      "applicationUrl": "http://0.0.0.0:15432",
      "environmentVariables": {
        "ASPNETCORE_ENVIRONMENT": "Development",
        "DOTNET_ENVIRONMENT": "Development",
        "ASPIRE_ALLOW_UNSECURED_TRANSPORT": "true",
        "ASPIRE_DASHBOARD_OTLP_ENDPOINT_URL": "http://localhost:19132",
        "ASPIRE_DASHBOARD_MCP_ENDPOINT_URL": "http://localhost:18119",
        "ASPIRE_DASHBOARD_MCP_API_KEY": "...", // 👈 specific key or disabled altogether
        "ASPIRE_RESOURCE_SERVICE_ENDPOINT_URL": "http://localhost:20202",
        "DOTNET_DASHBOARD_UNSECURED_ALLOW_ANONYMOUS": "true"
      }
    }
  }
}

As a note: it seems that when the aspire CLI is installed, the API key is not available in the UI: