Entropy0 SDK

AI agents fetch URLs, follow links, and act on domains they've never seen before. Most of the time that's fine. Sometimes it isn't — phishing infrastructure, newly registered lookalike domains, brand impersonation sites, or plain malware hosting.

Entropy0 adds a trust gate between your agent and the external web. One API call returns a machine-readable recommended action your agent can reason about before it fetches, navigates, or transacts.

Try it without signing up →

POST /v1/decide
{ "domain": "secure-login-verify-account.xyz" }

→ recommended_action: "deny"
  confidence: 91%
  signals: [NEWLY_REGISTERED_DOMAIN, BRAND_MISMATCH, CERTIFICATE_ANOMALY]

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Packages

Package	Registry	Description
entropy0-langchain	PyPI	LangChain tool — trust-gate URLs before agents fetch from them
@entropy0/express	npm	Express middleware — evaluate request targets through /v1/decide

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Quick start

LangChain (Python)

pip install entropy0-langchain

from entropy0_langchain import Entropy0Tool

tools = [Entropy0Tool(api_key="sk_ent0_xxxx")]
# Agent will call entropy0_trust_check before fetching any external URL

Express (Node.js)

npm install @entropy0/express

import { entropy0Guard } from "@entropy0/express";

app.use(entropy0Guard({ apiKey: process.env.ENTROPY0_API_KEY! }));
// Requests to flagged domains are blocked before your handlers run

Direct API

curl -X POST https://entropy0.ai/v1/decide \
  -H "X-API-Key: sk_ent0_xxxx" \
  -H "Content-Type: application/json" \
  -d '{"domain": "example.com"}'

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How it works

Each decision runs a deterministic pipeline — same inputs always produce the same output:

1. Classifies the domain (Clear Threat → Safe Known) using WHOIS, DNS, SSL, and threat intel feeds
2. Maps classification to a base action under your chosen policy
3. Shifts strictness based on interaction risk (fetch vs transactional vs privileged)
4. Applies confidence clamps — low-confidence negatives never hard-deny
5. Returns recommended_action + reason codes + uncertainty + bounded validity window

No probabilistic black boxes. Auditable, explainable, overridable.

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Examples

Example	Description
examples/rag-agent	LangChain agent that trust-gates every URL before fetching content

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Links

• Live playground — no sign-up required
• API reference
• Get a free API key — 150 scans/month, no credit card