Discovery

Limitguard publishes machine-readable discovery files for three AI agent protocols. All discovery endpoints are free and require no authentication.

Discovery Endpoints

Endpoint	Protocol	Purpose
`GET /.well-known/x402.json`	x402 Bazaar	AI marketplace service listing with pricing
`GET /.well-known/agent.json`	A2A (Agent-to-Agent)	Agent Card for capability discovery
`GET /.well-known/mcp.json`	MCP (Model Context Protocol)	Tool manifest for LLM agents
`GET /.well-known/security.txt`	RFC 9116	Security contact information
`GET /llms.txt`	llms.txt	Concise LLM-readable API summary
`GET /llms-full.txt`	llms.txt	Full LLM-readable API reference

All /.well-known/* requests bypass x402 payment middleware completely: no payment or API key needed.

x402 Bazaar Listing

Enables AI agents to discover available endpoints and their payment requirements automatically.

curl https://api.limitguard.ai/.well-known/x402.json

Response

{
  "service": "Limitguard.ai",
  "version": "1.0",
  "protocol": "x402-v2",
  "x402Version": 2,
  "discoverable": true,
  "description": "Limitguard is a lead validation service for lead generation agencies, B2B marketing and sales teams: it checks the company behind each lead against official business registers (full coverage in the Netherlands and Belgium), EU VAT and sanctions lists, ...",
  "capabilities": ["lead_verification", "entity_verification", "risk_scoring", "reputation_tracking", "compliance_monitoring", "wallet_verification"],
  "endpoints": [
    {
      "path": "/v1/entity/check",
      "method": "POST",
      "price_usdc": 1.05,
      "price_raw": 1050000,
      "description": "Full entity trust check across multiple verification layers: ...",
      "category": "trust_intelligence"
    },
    {
      "path": "/v1/leads/verify",
      "method": "POST",
      "price_usdc": 0.27,
      "price_raw": 270000,
      "description": "Lead verify for one NL or BE sales lead: is it a real, active company? ...",
      "category": "other"
    }
  ]
}

Trimmed here: the live response lists every priced endpoint, each with its inputSchema, plus payment (networks and assets), extensions, a2a and sla blocks. price_raw is the default (fresh) price in USDC 6-decimal units. See Pricing for the complete, current table. Also available at /v1/sales/listing for the same data.

A2A Agent Card

Google’s Agent-to-Agent (A2A) protocol for agent capability discovery.

curl https://api.limitguard.ai/.well-known/agent.json

Returns capabilities, skills, and how to invoke Limitguard as an A2A agent. Other agents can discover what Limitguard can do and how to interact with it programmatically.

MCP Manifest

Model Context Protocol tools for LLM agents (Claude, GPT-4, etc.).

curl https://api.limitguard.ai/.well-known/mcp.json

Returns tool definitions that LLM agents can use to call Limitguard endpoints as native tools. See the AI Agent Integration guide for usage examples.

llms.txt

Standard machine-readable format for LLM consumption.

# Concise summary for quick context loading
curl https://api.limitguard.ai/llms.txt

# Full reference with all endpoints, pricing, and examples
curl https://api.limitguard.ai/llms-full.txt

Cross-Sell Recommendations

AI agents calling one endpoint can discover complementary services:

curl "https://api.limitguard.ai/v1/sales/recommendations?current_endpoint=/v1/risk/score" \
  -H "X-API-Key: lg_live_xxxxxxxxxxxxxxxxxxxx"

Needs an API key (a free or sandbox key works). Returns the complementary endpoints for the one you name, with their prices; for /v1/risk/score that is the full /v1/entity/check.

Integration Example

An AI agent discovering and using Limitguard autonomously:

import httpx

# Step 1: Discover capabilities
listing = httpx.get("https://api.limitguard.ai/.well-known/x402.json").json()
entity_check = next(e for e in listing["endpoints"] if e["path"] == "/v1/entity/check")

# Step 2: Check price (the default fresh price, in USDC 6-decimal units)
amount = int(entity_check["price_raw"])

# Step 3: Build x402 payment and call
from my_wallet import build_x402_payment
x_payment = build_x402_payment(amount=amount)

response = httpx.post(
    "https://api.limitguard.ai/v1/entity/check",
    headers={"X-PAYMENT": x_payment},
    json={"entity_name": "Acme Corp BV", "country": "NL"},
)
print(response.json()["trust_score"])  # 87

// Step 1: Discover capabilities
const listing = await fetch("https://api.limitguard.ai/.well-known/x402.json")
  .then((r) => r.json());
const entityCheck = listing.endpoints.find((e) => e.path === "/v1/entity/check");

// Step 2: Check price (the default fresh price, in USDC 6-decimal units)
const amount = Number(entityCheck.price_raw);

// Step 3: Build x402 payment and call
const xPayment = await buildX402Payment(amount);

const response = await fetch("https://api.limitguard.ai/v1/entity/check", {
  method: "POST",
  headers: { "X-PAYMENT": xPayment, "Content-Type": "application/json" },
  body: JSON.stringify({ entity_name: "Acme Corp BV", country: "NL" }),
});
const result = await response.json();
console.log(result.trust_score); // 87

Get Started

Core Concepts

Guides

Post-mortems

Discovery Endpoints

x402 Bazaar Listing

A2A Agent Card

MCP Manifest

llms.txt

Cross-Sell Recommendations

Integration Example

​Discovery Endpoints

​x402 Bazaar Listing

​A2A Agent Card

​MCP Manifest

​llms.txt

​Cross-Sell Recommendations

​Integration Example

Discovery Endpoints

x402 Bazaar Listing

A2A Agent Card

MCP Manifest

llms.txt

Cross-Sell Recommendations

Integration Example