Other agents
Every agent other than Claude Code and Codex runs over the Agent Client Protocol; how each kind is installed, updated and set up.
Every agent other than Claude Code and Codex runs over the Agent Client Protocol (ACP). The list of agents is built into Kettu and follows the ACP Registry, with each package’s version set by Kettu. You cannot add an agent that is not on the list. See them all on the home page.
How each kind is installed
| Kind | Examples | What you need | What happens |
|---|---|---|---|
| npm package | Gemini CLI, GitHub Copilot, Qwen Code, Cline | Node.js with npm; some need Node.js 22 or later | Install puts the package in Kettu’s data folder, and it runs on your Node.js |
| Python package | fast-agent, Minion Code | uv | Runs with uvx, which installs it on first use |
| Release archive | Cursor, goose, Junie | Nothing | Your own copy on PATH runs first. Otherwise Install downloads the archive the ACP Registry lists into Kettu’s data folder |
| Your own program | OpenCode, Hermes Agent | The program, installed your way | Kettu starts it in its ACP mode, such as opencode acp. For OpenCode, Install offers its maker’s ways |
Install is in Settings › Harnesses, beside the agent or on its page. npm installs use your own npm, so the mirrors and proxy in your .npmrc apply. A downloaded archive is checked against its SHA-256 when the registry gives one. Pi runs through the adapter pi-acp, which also needs your own pi 0.81.0 or later on PATH.
If an install fails, the agent’s Harnesses page says why, and you can try again. If your program is somewhere PATH does not reach, click Choose binary… on the agent’s Harnesses page. After you install something in your own terminal, click Reload environment at the bottom of Settings › Harnesses.
Updates
Kettu checks npm once a day for the packages it installed, and right away when you click Check for updates. Update installs the new version next to the current one: running sessions keep going, and the agent uses it from its next start. If it cannot install, the current version stays. When a Kettu update needs a newer version of a package, the next start installs it, and the older one keeps running if that fails.
Kettu does not update archives, uvx packages or programs you installed yourself. Update your own programs the way you installed them, then click Reload environment.
Two settings pages
The agent’s page in Settings › Harnesses shows the program:
- Version, with Check for updates.
- Program: the path and version of what runs, with Choose binary… and Reset.
- Installed by Kettu: the package and its version, with Update to when there is an update.
- Advanced: the Launch command with Copy launch command, and for a package Kettu installed, Reinstall to delete it and install it again, and the Node.js version it runs on.
Its page in Settings › Agents shows the agent you work with: its account and email when the agent reports them, Sign out where the agent supports it, Plan usage when it reports limits, and its configuration files where Kettu knows them.
Signing in
An agent that needs a sign-in says so in the agent menu and on its Settings › Agents page. A method that runs a command has Sign in in terminal, which runs it in Kettu’s terminal. A method the agent handles itself is a button named the way the agent names it. When the agent names no method, sign in with its own command line, then retry.
Hiding an agent
Only Claude Code and Codex can carry more than one agent. Every other agent has its one default agent, which cannot be deleted. To keep it out of the agent menu, turn on Hide in the agent menu on its Settings › Agents page.