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Agent Browser Gateway Docs

Architecture

ABG is built from three local pieces:

  • A browser extension in the user’s browser profile.
  • A native Gateway app that runs on the user’s machine.
  • The abg CLI used by agents, scripts, and humans.
Browser tab + ABG extension
        |
        | WebSocket on 127.0.0.1
        v
Gateway app
  - permission manager
  - plugin host
  - audit log
        |
        | local IPC
        v
abg CLI
        |
        v
AI coding agent

Extension

Section titled “Extension”

The extension is the browser-side consent surface. In normal per-tab mode, ABG starts with no visible tabs. The user shares a specific tab from the popup, and the extension sends tab metadata and command responses to the local Gateway.

The optional all-tabs mode is for isolated profiles and sandbox machines. It requests optional host access only after the user enables it, and turning it off revokes the all-tabs entries again.

Gateway

Section titled “Gateway”

The Gateway listens on loopback and owns the runtime state:

  • connected extension instances,
  • shared tabs,
  • operation approval state,
  • loaded plugins,
  • local audit logging,
  • app settings and plugin state.

The production app uses the normal Gateway state directory. The development app uses a separate port and profile-specific state so development plugins and settings do not mutate production state.

CLI

Section titled “CLI”

abg is the stable interface for agents. It keeps the integration agent-agnostic: any tool that can run shell commands can inspect and operate a shared tab.

The CLI also makes debugging simple. If an agent says it cannot see a tab, the human can run:

Terminal window
abg status
abg tabs --compact
abg audit --lines 20

Plugins

Section titled “Plugins”

Plugins are local JavaScript modules loaded by the Gateway. They can transform browser data, add domain-specific Markdown extraction, or register higher-level commands. Plugin-issued tab operations use the same approval and audit path as CLI operations.

See Plugins for install and authoring details.

Platform roadmap

Section titled “Platform roadmap”

Chrome is the first browser target. Firefox support is being added through a browser adapter and a Firefox extension target. Safari, mobile browsers, and remote pairing are future tracks and require separate permission and pairing designs.