Connect agents

Connect Cursor

Cursor's MCP picker + Nomos = your editor agent can call SaaS APIs without ever touching a token.

Cursor speaks the Model Context Protocol (MCP) natively. Nomos ships an MCP server (@auto-nomos/mcp-server) that exposes every connected SaaS as a set of tools to Cursor — each call goes through your Nomos policy first, every approval lands on your phone, every action lands in the audit chain.

Before you start

Cursor 0.42+ (older versions: MCP picker lives under Settings → Beta Features).
A Nomos App with an API key (Get started → Register your first App).
At least one Connection (e.g. GitHub).

Step-by-step

1
Open Cursor's MCP settings
Cursor → Settings → MCP → Add new server.
Cursor MCP picker. 'Add new server' is the entry point.
2
Pick command-based config
Cursor calls npx with the MCP server package. Use this exact block:
jsonc
```
{
  "name": "Nomos",
  "command": "npx",
  "args": ["-y", "@auto-nomos/mcp-server@latest"],
  "env": {
    "NOMOS_CONTROL_URL": "https://control.auto-nomos.com",
    "NOMOS_API_KEY": "nk_live_…",
    "NOMOS_PDP_URL": "https://pdp.auto-nomos.com"
  }
}
```
Replace the API key with the one you copied from the App detail page.
Cursor expects command + env. Pin a specific version (e.g. @0.0.20) for stable deployments.
3
Restart Cursor + verify tools
Cursor reloads MCP servers on launch. Quit and re-open. The Tools picker (next to the chat input) now shows tools like github_issue_list, github_pr_create, slack_message_post — one per connected provider, one per allowed command.
One tool per allowed command. Disabled tools are policy-gated.
4
Ask Cursor to do something
In the chat: "List the open issues on acme/app." Cursor sees the github_issue_list tool, the MCP server asks Nomos for a UCAN, the PDP allows it, GitHub responds, Cursor reads the list.
Tool call + response inline in the chat. The OAuth token never enters Cursor's process.

Verify it worked

Cursor's tool picker shows tools prefixed with the connected providers (github_*, slack_*, etc.).
Asking a question that requires a tool call results in a real upstream response.
The Nomos audit page (/app/audit) shows one row per tool call, attributed to your App's DID.

When something asks for approval

The MCP server runs inside Cursor's process — but the approval lives on your phone (or browser). If a tool call hits a step-up gate, the MCP server:

Returns a deny + push notification.
You tap the notification, sign with your passkey.
The MCP server retries the same call with the cosigner UCAN.

Cursor sees a brief pause, then the tool returns the result. You don't need to do anything in Cursor.

Step-up gate examples

By default, the github:read-only template never triggers step-up. Templates like github:safe-default, github:exec, ssh:exec-step-up, and filesystem:delete-step-up do — Cursor will pause for ~3 seconds while the push lands and you approve.

Locking down a Cursor laptop

Each laptop should have its own API key with the narrow member role.

bash

# in Cursor's env (Settings → MCP → edit server → env)
NOMOS_API_KEY="nk_live_for_my_laptop_only"

When the laptop is decommissioned, revoke that one key from the App detail page — existing UCANs continue to work until expiry, but no new ones can be minted.

Common failures

Cursor's tool picker is empty after restart+
MCP server didn't start. Open Cursor → Output → MCP, look for the Nomos process. Most common cause: wrong NOMOS_CONTROL_URL (missing https://, trailing slash) or wrong API key. Fix env and restart.
Every tool call returns 'unauthorized'+
API key was revoked or belongs to a different org. Re-issue from the App detail page and update Cursor's MCP env.
Tool calls show but always deny+
No policy attached, or the policy doesn't permit the command. Open the audit row — the `reason` field tells you which. Attach `github:read-only` or `github:safe-default` to the App as a sanity check.

Next →Connect Claude DesktopSame MCP server, different host.Next →Pick a policy template20 starter policies across 12 providers.