Agents

Arbitr does not include an agent of its own. It drives the coding agent CLIs that are already on your Mac, and each one keeps its own account.

Supported agents

Cursor is the cursor-agent binary, not the cursor command that opens the editor.

Install and sign in first

Install each agent the way its own documentation says, and sign in with its own command — claude, codex login, cursor-agent login. Arbitr never asks for an API key for these agents and never stores one.

That also means an agent that works in your terminal is the only kind Arbitr can run. If a prompt fails with an authentication error, sign in again in the terminal and try once more.

Add an agent

Open Settings with ⌘, and pick Agents.

Discovered agents lists what Arbitr found. Press Add next to one to start using it.

If an agent is installed somewhere Arbitr can’t find automatically, add it by hand: select the agent, then type the path into the Binary path field or press Browse…. An agent that is not installed simply does not appear in the list.

Models

Each agent has its own model list under Settings → Agents. Turn a model off to keep it out of the picker. Press Refresh to reload the list, or Add custom model to enter a slug the list does not carry.

Choose per prompt

Above the input box are three pickers: agent, model, and effort. Use ⇧⌘H, ⇧⌘M and ⇧⌘E to open them, and ⌘1 to ⌘9 to pick a row.

Changing the agent resets the model to that agent’s default, and changing the model resets the effort. Each conversation remembers what you used last, so the next prompt in it starts from the same three.

No account

Arbitr itself has no account, licence or subscription. Nothing to sign up for, nothing to activate.

The usage limits widget in the sidebar is a separate, optional thing. It signs in to your provider only to read your own remaining quota, and it has no part in running agents. You can use Arbitr without ever adding one.