Herdbell

Herdbell is a native macOS menu bar app for developers who run several AI coding agents at once. It watches Claude Code, OpenAI Codex, Cursor and Google Antigravity through their own local hooks, and alerts you when one needs a permission, a reply, or has finished or errored. The site states that it has no account, no cloud backend, and never calls an AI model.

What It Is

Herdbell is a session monitor and quick-response layer for coding agents. It adds hooks to each agent's settings (saving a timestamped backup first) and lists every session in one dashboard with agent, project, status, and elapsed time. Statuses include needs permission, waiting for reply, working, finished, and error. Your pointer glows in a status color when something needs you, and a shortcut opens a bar over your current work.

Responding Without Leaving Your Flow

From the bar you can allow or deny a command, send a quick reply or typed message, or hand the chat to another agent. Allow and Deny work in Herdbell for Claude Code, Codex and Cursor; for Antigravity the request is shown and approved in Antigravity itself. Replies on completion work for all four. Risky commands ask twice, and if you are away, the agent falls back to its own prompt after a configurable wait (5 minutes by default). Each session also keeps an ordered activity log of commands, edits and errors.

Context Bridge

Context Bridge is meant for cases such as hitting a usage limit. Pressing the handoff shortcut makes Herdbell read the local session transcript and project files and write a short handoff covering the goal, what is done, decisions, what is still open, files changed, and commands run. You can copy a quick or full version, save it as HANDOFF.md, or open it in another agent. It runs locally without an AI model, so its completeness depends on what the chat and project contain.

Privacy and Setup

Herdbell is built in Swift, SwiftUI and AppKit and requires macOS 14 Sonoma or later plus at least one supported agent. Session data stays on the Mac; network access is used only for license checks and update checks. Agents can be disconnected individually, which removes only Herdbell's hooks, and a Delete all my data option clears chats, the activity log, attachments and drafts.