Agent Protocol Inspector via x402 Wire v2: A Technical Tutorial

ContextIQ's Agent Protocol Inspector now offers an x402 wire v2 endpoint at $0.02 per call that scans any URL for MCP, A2A, ARD, and llms.txt support, payable via an API key or the @x402/fetch library on Base (eip155:8453). A live scan of ContextIQ's own domain returned detectedCount: 0, with mcp, a2a, and ard all not_detected and llmsTxt found at https://contextiq.trango-compute.com/llms.txt. Each protocol returns status confirmed, indicated, or not_detected with evidence naming the specific .well-known path or response header checked.

Agent Protocol Inspector via x402 Wire v2: A Technical Tutorial Call ContextIQ's Agent Protocol Inspector via x402 wire v2 to detect MCP, A2A, ARD, and llms.txt support on any URL, paid with @x402/fetch or an API key. Agent Protocol Inspector https://contextiq.trango-compute.com/agent-readiness-detector checks whether a URL supports MCP Model Context Protocol , A2A Agent2Agent , ARD Agentic Resource Discovery , or publishes an llms.txt file — the signals that tell you whether a service is actually built to be used by an autonomous agent, or just a regular website an agent happens to be able to scrape. This is a tutorial for its x402 wire v2 endpoint. The Endpoint POST /api/v1/agent-protocol-inspector/x402-v2 Price: $0.02 per call Body: { "url": "<URL to scan " } The 402 Challenge curl -i -X POST https://contextiq.trango-compute.com/api/v1/agent-protocol-inspector/x402-v2 \ -H "Content-Type: application/json" \ -d '{"url":"example.com"}' Same shape as every other ContextIQ v2 route: the actual challenge is base64-encoded JSON in the PAYMENT-REQUIRED response header, not the body. { "x402Version": 2, "resource": { "url": "https://contextiq.trango-compute.com/api/v1/agent-protocol-inspector/x402-v2" }, "accepts": { "scheme": "exact", "network": "eip155:8453", "amount": "20000", "payTo": "0x4eba5ea3cf0f3fc307099317e17e54390f7a4c58", "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913" } , "extensions": { "bazaar": { "info": { "input": { "type": "http", "method": "POST", "schema": { "properties": { "url": { "type": "string" } }, "required": "url" } } } } } } Option A: API Key curl -X POST https://contextiq.trango-compute.com/api/v1/agent-protocol-inspector/x402-v2 \ -H "Authorization: Bearer sk live ..." \ -H "Content-Type: application/json" \ -d '{"url":"example.com"}' Option B: Pay With x402, No API Key js import { createWalletClient, http } from "viem"; import { privateKeyToAccount } from "viem/accounts"; import { base } from "viem/chains"; import { wrapFetchWithPayment } from "@x402/fetch"; const account = privateKeyToAccount process.env.WALLET PRIVATE KEY as 0x${string} ; const client = createWalletClient { account, transport: http , chain: base } ; const fetchWithPayment = wrapFetchWithPayment fetch, client ; const res = await fetchWithPayment "https://contextiq.trango-compute.com/api/v1/agent-protocol-inspector/x402-v2", { method: "POST", headers: { "Content-Type": "application/json" }, body: JSON.stringify { url: "example.com" } , } ; console.log await res.json ; The Response Real output from a live scan ContextIQ's own domain, run today : { "target": "https://contextiq.trango-compute.com", "origin": "https://contextiq.trango-compute.com", "protocols": { "mcp": { "status": "not detected", "evidence": }, "a2a": { "status": "not detected", "evidence": }, "ard": { "status": "not detected", "evidence": } }, "llmsTxt": { "found": true, "url": "https://contextiq.trango-compute.com/llms.txt" }, "detectedCount": 0 } Each protocol's status is confirmed found and validated , indicated some signal, e.g. a route exists but didn't fully validate , or not detected . evidence names exactly what was checked and found, so a confirmed result isn't a black-box claim — you can see the specific .well-known path or response header that triggered it. detectedCount is a quick sum across the three protocols; llmsTxt is tracked separately since it's a content convention, not an agent-callable protocol. Worth internalizing from real-world scanning: most of the internet, including plenty of services that are perfectly usable by an agent via plain HTTP, will show detectedCount: 0 . That's expected, not a failure — this tool answers "does this URL declare agent-native protocol support," not "can an agent use this at all." Try It Agent Protocol Inspector https://contextiq.trango-compute.com/agent-readiness-detector is free from the dashboard, or callable via the API above for checking a counterparty's agent-readiness before your own agent decides how to integrate with it. Follow Trango Compute on LinkedIn We post updates on new tools, context engineering patterns, and LLM cost research. Follow on LinkedIn https://www.linkedin.com/company/trango-compute