複数のAIエージェントを1画面にまとめるターミナルマルチプレクサ「herdr」herdr is a terminal multiplexer that aggregates the status of multiple AI…

Multiple AI coding agents

herdr brings the status of multiple AI coding agents, including Claude Code, Codex, and Cursor, into one terminal screen. This matters when several agents are running in parallel: otherwise, each application must be opened separately to determine which agent has finished its work and which has stopped while awaiting approval.

Terminal multiplexer

herdr is a terminal multiplexer that can recognize the state of AI coding agents. A terminal multiplexer places multiple terminals inside one terminal screen so they can be handled simultaneously. tmux is a representative example of this type of software, and herdr belongs to the same family.

Although multiplexers can split the screen and switch between tabs, their defining characteristic is that sessions remain alive. A normal terminal ends the processes running inside it when its window is closed. A multiplexer instead remains active as a server in the background, while the visible terminal acts only as a window into that server.

Closing the window therefore does not end the process. Reconnecting from another terminal makes it possible to continue viewing the same session.

Status in a single screen

This persistent-session model suits agents that may run for several minutes or tens of minutes after a task is assigned. The visible terminal can be closed while the agent continues running.

tmux can also run several agents in parallel, but it treats the contents of each pane as text. It cannot identify which pane is waiting for input, so users still have to inspect panes one by one. That recreates much of the repeated checking involved in opening separate applications.

Awaiting approval

herdr reads the screen contents and determines when an agent is requesting approval. It then displays that result in a sidebar, allowing users to check agent states without repeatedly moving between panes or applications.

The article presents this status recognition as the main reason to use herdr. It also contrasts the approach with tmux’s primarily keyboard-driven operation, which requires users to learn shortcuts before they can begin using it effectively.