agent-browser-plugin-allow-loopback

agent-browser-plugin-allow-loopback

Launch mutator plugin for agent-browser that allows Chrome localhost handoff flows by treating loopback addresses as public for Local Network Access.

The plugin appends one Chrome launch argument:

--ip-address-space-overrides=127.0.0.0/8=public,[::1]/128=public

This is useful for SSO/native app handoff flows that connect from a website to a local helper on 127.0.0.1 or ::1. Because the plugin returns a structured JSON array through launch.mutate, the comma in the Chrome flag is preserved.

Install

agent-browser plugin add agent-browser-plugin-allow-loopback

Manual config:

{
  "plugins": [
    {
      "name": "allow-loopback",
      "command": "agent-browser-plugin-allow-loopback",
      "capabilities": ["launch.mutate"]
    }
  ]
}

Security

This plugin changes Chrome's address-space classification for all loopback targets in the launched browser process. It is process-wide, not origin-scoped. Use LoopbackNetworkAllowedForUrls managed policy when you need a narrower origin-scoped exception.