Cursor

Happier runs Cursor through its local cursor-agent CLI, over the Agent Client Protocol. Once the CLI works on a machine, happier cursor starts a session there that you can read, steer and approve from your phone, a browser, or another computer.

What you need first

Happier drives your coding agent; it does not ship one. Before happier cursor will do anything, cursor-agent has to be installed and signed in on the machine that will run the session. If it does not work in that machine's terminal today, it will not work through Happier either.

Install the CLI

Follow Cursor's current CLI installation instructions, then confirm it runs:

cursor-agent --version

In Happier you can check the same thing without leaving the app: open Settings → AI & Agents → AI backends → Cursor to see whether the CLI was found on the selected machine.

Happier looks for cursor-agent on PATH (cursor-agent.cmd on Windows), and falls back to agent. If yours lives somewhere unusual, set HAPPIER_CURSOR_PATH to the absolute path of the executable in the environment the Happier CLI or daemon runs in.

Authenticate

Two routes, and Happier accepts either.

An API key. Set CURSOR_API_KEY in the environment used by the Happier CLI or daemon. Happier detects the variable without copying its value into session metadata or logs.

Cursor's own login. Sign in with the cursor-agent CLI as you normally would. Happier reads the cached status by running Cursor's own read-only status command, so Settings → AI & Agents → AI backends → Cursor reflects your real login state without you having to re-authenticate through Happier.

That status check is safe to run in the background, so unlike some agents, Cursor's login state stays current on its own.

Start a session

happier cursor

Or pick Cursor as the AI backend in the new-session flow on any client.

Models

Happier asks Cursor which models it offers and shows you that list — it does not carry a hardcoded catalog that can drift. Selecting one applies it through Cursor's own ACP configuration, so what you see selected is what Cursor confirmed.

Cursor does not accept arbitrary model ids: you choose from the models it advertises. If you need one that is not listed, it is Cursor's CLI that decides, not Happier.

Permission modes

Happier's permission modes map onto real cursor-agent flags rather than being advisory:

See Permissions for what those modes mean across agents.

Limits

Cursor's own capabilities decide most of these, and the agent capability tables carry the authoritative, generated version. The ones worth knowing before you start:

• Images go one way. Cursor can generate images, and they arrive in Happier as durable session media that survives a reload. Happier does not send images to Cursor — attaching a screenshot to a prompt is not available on this agent.
• Resume is experimental. Happier stores the Cursor session identity and can ask to resume after the provider process restarts, but it checks at runtime whether the installed CLI actually supports it rather than assuming.
• No session browsing, forking or rollback through Cursor. Happier cannot list your existing Cursor sessions, fork one natively, or roll a conversation back. Where Happier offers those actions, the Cursor routes are shown as unavailable with the reason, rather than silently doing something else. Happier's own replay fork is a separate mechanism and is not affected by this.
• Tool calls run over the shell bridge, and that path is experimental for Cursor.
• One session per machine at a time. Cursor's local control is exclusive, and Happier cannot attach to a cursor-agent process you started yourself.
• No plan mode. Cursor exposes a single session mode.

Advanced

HAPPIER_CURSOR_API_ENDPOINT points cursor-agent at a non-default API endpoint. Set it in the environment the Happier CLI or daemon runs in; Happier passes it through on launch.

When it goes wrong

"Cursor not found"

1. Confirm cursor-agent --version works on the machine that will run the session — not on your laptop, if the session runs elsewhere.
2. Restart Happier after installing the CLI so detection re-runs.
3. If the binary is outside the usual locations, set HAPPIER_CURSOR_PATH to its absolute path.

Sessions fail to start, or the model list is empty

1. Check the login state under Settings → AI & Agents → AI backends → Cursor.
2. If you authenticate by key, confirm CURSOR_API_KEY is present in the Happier CLI or daemon environment — not just in your interactive shell. A daemon started before you exported it will not see it.
3. Update cursor-agent. An older CLI can accept an ACP connection and then not advertise a model inventory.

Related

• Agent capabilities — the generated matrix for all agents
• Provider authentication — the shared authentication flow
• Model and engine selection
• Permissions