Authentication

Nansen account API calls accept a selected nansen:api browser session or conventional API key with the same permissions. NANSEN_API_KEY takes precedence; optional primaryEnv preserves configured-key injection. Run nansen auth status for offline selection. Cached access expiry alone permits automatic renewal during an authorized task. Stop on anonymous selection, invalid state, blocked/uncertain renewal or actual auth failure; never drop a credential or fall back to anonymous x402 payment. Browser login does not grant wallet signing, privileged service identity or a persistent MCP integration key. Preserve all confirmation, signing, sanctions and geographic checks below. Browser login is available in CLI 2.0.0 within the macOS arm64 preview scope.

Alert Webhook Listener

Set up a local HTTP server to receive Nansen smart alert webhook payloads in real-time.

How It Works

Nansen smart alerts support a webhook channel type. When an alert fires, Nansen sends an HTTP POST with a JSON payload to your webhook URL. This skill sets up:

1. A local HTTP server (Node.js, zero external dependencies) that receives and displays alert payloads
2. HMAC-SHA256 signature verification so only authentic Nansen payloads are accepted
3. A public tunnel so Nansen's servers can reach your local machine

This skill does NOT create or modify alerts. It sets up the listener infrastructure and then provides a summary of what the user needs to do to start receiving alerts.