2035840 - Add documentation and guidelines about MCP sandboxing

Status: NEW

(Developer Infrastructure :: Firefox MCP, task)

Description

[Julian Descottes [:jdescottes]]

Sandboxing MCP servers spawned by AI agents is not trivial.

In Claude's case, the MCP servers are not impacted by the sandbox of Claude code.

There is an alternative which is to start the MCP wrapped in srt (sandbox runtime) provided by Anthropic at https://github.com/anthropic-experimental/sandbox-runtime

      "mcpServers": {
        "firefox-devtools": {
          "type": "stdio",
          "command": "srt",
          "args": [
            "node",
            "/Users/username/path/to/firefox-devtools-mcp/dist/index.js",
            "--profile-path",
            "/path/to/profile/firefox-devtools-mcp",
            "--enable-script"
          ]
        }
      },

• ~/.srt-settings.json

{
  "filesystem": {
    "denyRead": [],
    "allowWrite": ["."],
    "denyWrite": []
  },
  "network": {
    "allowedDomains": [],
    "deniedDomains": []
  }
}

We will need to test this in more details. At the moment I verified that with a strict sandbox which didn't have access to the --profile-path folder, the MCP is not allowed to start firefox. Next step will be to find good defaults we can recommend for a safer usage of the MCP.