Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add nansen-ai/nansen-cli --skill nansen-alerts-webhook-listenergit clone --depth 1 https://github.com/nansen-ai/nansen-cliWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/nansen-ai/nansen-cli/nansen-alerts-webhook-listener)<a href="https://agentmods.dev/skills/nansen-ai/nansen-cli/nansen-alerts-webhook-listener"><img src="https://agentmods.dev/badge/skills/nansen-ai/nansen-cli/nansen-alerts-webhook-listener/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/nansen-ai/nansen-cli/nansen-alerts-webhook-listener"><img src="https://agentmods.dev/badge/skills/nansen-ai/nansen-cli/nansen-alerts-webhook-listener.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00048 | $0.03997 |
| Opus 5 | $0.00024 | $0.01998 |
| Sonnet 5 | $0.00010 | $0.00799 |
| Haiku 4.5 | $0.00005 | $0.00400 |
Grade C, and why
nansen-alerts-webhook-listener scanned grade C with 2 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 9d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Downloads and executes remote codehighSupply chain
curl | sh runs whatever the server returns today, which is not necessarily what it returned when this was reviewed.
curl -s http://127.0.0.1:4040/api/tunnels | node -e "process.stdin.on('data',d=>console.log(JSON.parse(d).tunnels[0]?.public_url))" Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
const res = await fetch(url, { How it starts
The opening of the file, as written. The whole thing — 387 lines — stays where its author put it; the contents beside it link to each section on GitHub.
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:
- A local HTTP server (Node.js, zero external dependencies) that receives and displays alert payloads
- HMAC-SHA256 signature verification so only authentic Nansen payloads are accepted
- 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.
OpenClaw users: If OpenClaw is running locally on the same machine, the webhook server can forward verified alert payloads to OpenClaw's Gateway (/hooks/agent), triggering an agent turn for each alert. Set the OPENCLAW_GATEWAY_URL env var to enable this. See the OpenClaw Integration section below.
Security Warning
Before proceeding, inform the user:
This skill starts an HTTP server on your machine and exposes it to the internet via a tunnel (ngrok or localtunnel). While the server only binds to localhost (
127.0.0.1) — meaning no one on your local network can access it directly — the tunnel creates a public URL that anyone on the internet can send requests to.Mitigations in place:
- HMAC-SHA256 signature verification rejects all requests not signed by Nansen
- 1 MB body size limit prevents memory abuse
- Only
POST /webhookandGET /healthare accepted; everything else returns 404You should be aware that:
- The tunnel URL is publicly discoverable (ngrok URLs can be enumerated)
- Unsigned requests still reach your machine — they're rejected, but the connection is made
- Stop the tunnel when you're done to close the public endpoint
Wait for the user to confirm they want to proceed before continuing.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 9d ago First seen · 387 lines · 48 tokens per session scan C 260da87c7bab
nansen-alerts-webhook-listener is a skill published in the GitHub repository nansen-ai/nansen-cli (135 stars, last pushed today), licensed MIT. It adds 48 tokens to every session and 3,997 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it C with 2 findings (downloads and executes remote code, makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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