# Set up your agent

Niv doesn't bring its own AI model to the chat. It runs the command-line agent you install, signed in with your own account. What you type, and the notes it reads, go from your device to that agent's provider, under its terms.

## Install an agent

Install one in Terminal, then sign in with it once. These are the commands Niv shows for each:

- **Claude Code**: `npm install -g @anthropic-ai/claude-code`, then run `claude` to sign in.
- **Codex**: `npm install -g @openai/codex`, then `codex login`.
- **Cursor**: `curl https://cursor.com/install -fsS | bash`, then `cursor-agent login`.
- **OpenCode**: `npm install -g opencode-ai`, then `opencode auth login`.
- **Grok**: install the Grok CLI from x.ai/cli, then `grok login`.

Niv finds agents the same way your shell does, so an agent you update in Terminal is the one Niv uses next time it checks.

### Antigravity

Antigravity is different: Niv downloads Google's official runtime for you, only when you ask. In **Settings › AI**, choose **Download the runtime**, then **Sign in with Google**. The sign-in happens in your browser. After you approve, the browser lands on a page that looks broken. That's expected: copy the full address from the address bar, paste it into Niv, and choose **Finish sign-in**.

## Check what Niv found

**Settings › AI › CLI tools** shows each agent, its version and where Niv found it.

- **Check again** looks again, after you install or update one.
- **Use a specific binary…** points Niv at one you choose.
- **Let Niv pick the newest** goes back to the default: when several are installed, Niv uses the newest.

In the chat's **Model** list, each agent shows whether it's ready, needs a sign-in, or wasn't found.

![Settings › AI › CLI tools, showing an agent Niv found and its version](https://niv.md/docs-media/settings-ai-cli.dark.png)

## Instruction files

`AGENTS.md` and `CLAUDE.md` at the top of your folder tell the agent how to work here: its tone, which files it may edit, and how to link notes. They are plain notes; open and edit them like any other.

In **Settings › AI › Instruction files**, Niv shows whether each file is in place. If one is missing, Niv can create it with its defaults. **Restore defaults…** replaces your file with the defaults, after copying your current one to the folder's trash.

These two files stay on this device. See [Local-only files](/p/docs/local-only-files).

## Your agent's own tools

If you set up MCP servers for Claude Code or Codex, Niv's chat uses them too. **Settings › AI** lists them under **Claude MCP servers** and **Codex MCP servers**, with whether each is connected. Whether a tool call asks you first depends on the access level. See [Access levels](/p/docs/access-levels).

## Niv's own AI

Niv's own AI is on the way. Today, the chat runs the agent you install.

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Published with [Niv](https://niv.md/) in the Space Docs.