Connect Your Agent: Claude Desktop, Cursor, and More

Every agent that talks to Nebula needs a bearer token — a short string that starts with nbl_live_…. This token tells the Hub which wallet to use, which policy to enforce, and how to attribute transactions in your dashboard. This page explains how to create that token and how to wire it into whichever client you are using.

Getting your token

Sign in at nebulaonchain.xyz.
Go to the Connect page in the sidebar.
Click New Agent, give it a descriptive name, and click Create.
Copy the nbl_live_… token immediately — it is only shown in full once. If you lose it, you can regenerate a new token from the dashboard; the old token will stop working.

Each agent you create gets its own token and its own row in the Approvals and Activity views. Give agents meaningful names like cursor-dev, claude-research, or prod-payment-bot so you can tell them apart in the dashboard.

Connection options

Claude Desktop
Cursor
Claude Code
Remote MCP (Streamable HTTP)

Open ~/Library/Application Support/Claude/claude_desktop_config.json on macOS (or %APPDATA%\Claude\claude_desktop_config.json on Windows). Add the nebula entry inside mcpServers:

claude_desktop_config.json

{
  "mcpServers": {
    "nebula": {
      "command": "npx",
      "args": ["-y", "@nebula/mcp"],
      "env": {
        "NEBULA_TOKEN": "nbl_live_…"
      }
    }
  }
}

Save the file and restart Claude Desktop. Claude will launch @nebula/mcp as a subprocess on startup and keep it running for the session.

Open Cursor Settings → MCP (or edit ~/.cursor/mcp.json directly) and add:

Cursor MCP config

{
  "mcpServers": {
    "nebula": {
      "command": "npx",
      "args": ["-y", "@nebula/mcp"],
      "env": {
        "NEBULA_TOKEN": "nbl_live_…"
      }
    }
  }
}

Toggle the Nebula server off and back on in the MCP settings panel to pick up the change without restarting Cursor.

Claude Code reads MCP configuration from the same claude_desktop_config.json file, or you can pass the token as an environment variable when launching:

NEBULA_TOKEN=nbl_live_… claude

If you prefer a project-scoped config, create .claude/mcp.json in your project root with the same JSON structure shown for Claude Desktop.

For hosted agents that cannot run a local subprocess, the Hub exposes a Streamable HTTP MCP endpoint directly. Send all tool calls as POST requests to:

POST https://nebulaonchain.xyz/mcp
Authorization: Bearer nbl_live_…
Content-Type: application/json

This is the right choice for serverless functions, Docker containers, or any environment where npx is not available. No package installation is needed — your agent talks to the Hub directly over HTTP.For automated OAuth flows (for example, hosted AI connectors), the Hub also supports OAuth 2.0 Dynamic Client Registration:

Discovery: GET /.well-known/oauth-authorization-server
Register: POST /api/oauth/register
Authorise: /authorize
Token: POST /oauth/token (access tokens expire after 30 days)

Environment variables

Variable	Required	Default	Description
`NEBULA_TOKEN`	Yes	—	Your `nbl_live_…` bearer token from the Connect page.
`NEBULA_HUB`	No	`https://nebulaonchain.xyz`	Override to point at a self-hosted Hub or local development instance (e.g. `http://localhost:3000`).

Verifying the connection

Once your client is configured, ask your agent:

“Call the Nebula ping tool.”

A successful response looks like:

Nebula is alive
2025-01-15T10:23:45.000Z

You can also ask for your wallet address to confirm the token is mapping to the right wallet:

“What is my Nebula wallet address?”

The agent will call get_address and return your Stellar public key (a G… string).

Security note: token vs secret key

Your NEBULA_TOKEN is a bearer token — it authorises tool calls but has no ability to sign Stellar transactions directly. Signing is always done inside the Hub, after policy checks pass. A Stellar secret key (which starts with S) would give anyone who holds it full, unconstrained control of the wallet. Nebula is designed so you never need to handle one.

Never put a Stellar secret key in your MCP configuration, environment files, or agent prompts. If any integration asks for an S… key, do not use it with Nebula.

If your NEBULA_TOKEN is ever exposed, go to the dashboard immediately, revoke the token, and create a new one. Your wallet funds remain safe because the token alone cannot sign transactions without the Hub’s policy layer.

​Getting your token

​Connection options

​Environment variables

​Verifying the connection

​Security note: token vs secret key

Getting your token

Connection options

Environment variables

Verifying the connection

Security note: token vs secret key