x402-buyer-mcp
The universal buyer agent for the x402 economy.
An MCP server that lets Claude Desktop, Cursor, and Claude Code users discover, pay for, and call any x402 endpoint — automatically. Ask Claude a question, and it pays for the answer with USDC.
No wallets. No crypto knowledge. No API keys. Just questions and answers.
What This Does
The x402 protocol lets AI agents pay for API calls with USDC. But until now, most tools in the ecosystem are sellers — endpoints that accept payment. This is the buyer — the agent that spends.
When you ask Claude "is stripe.com secure?" this MCP:
- Discovers the right x402 endpoint (Domain Shield — VirusTotal + DNS security)
- Pays $0.12 in USDC on Base via your AgentCash wallet
- Returns the full scored security report to Claude
- Claude synthesizes the answer naturally
You never touch a wallet. You never see a blockchain. You just get answers backed by premium data.
Install
Prerequisites
- Fund an AgentCash wallet (one-time, 2 minutes):
Follow the prompts to create a wallet and fund it with USDC on Base. $5 covers ~40 calls.npx agentcash install
Claude Desktop
Add to your claude_desktop_config.json:
{
"mcpServers": {
"x402-buyer": {
"command": "npx",
"args": ["-y", "x402-buyer-mcp"]
}
}
}
Cursor
Add to your .cursor/mcp.json:
{
"mcpServers": {
"x402-buyer": {
"command": "npx",
"args": ["-y", "x402-buyer-mcp"]
}
}
}
Claude Code
claude mcp add x402-buyer -- npx -y x402-buyer-mcp
Tools
x402_discover
Search for x402 endpoints that can answer a question.
"Find endpoints for domain security scanning"
"Search for company intelligence APIs"
"What x402 endpoints handle drug interactions?"
x402_call
Call any x402 endpoint with automatic payment.
"Call https://www.alderpost.co/api/domain-shield?domain=stripe.com"
"Call https://www.alderpost.co/api/company-xray?domain=hubspot.com"
x402_balance
Check your AgentCash wallet balance.
"What's my x402 balance?"
"How many calls can I afford?"
x402_research ⭐
The killer feature. Multi-endpoint parallel research. Give it a domain and it calls 3-5 endpoints simultaneously, returning a complete intelligence picture.
"Research stripe.com" → calls 5 endpoints (~$0.64):
- Domain Shield (security scan)
- Company X-Ray (firmographics)
- Threat Pulse (threat intel)
- Compliance Check (audit)
- Prospect IQ (contact info)
"Research ibuprofen" → calls 1 endpoint (~$0.10):
- Health Signal (FDA data + drug interactions)
"Research 123 Main St Milwaukee WI" → calls 1 endpoint (~$0.10):
- Property Intel (demographics + amenities)
Budget control: set max_cost to cap total spend per research call.
Endpoints in Registry
The built-in registry includes premium endpoints backed by paid data sources:
| Endpoint | What You Get | Price | Premium Source |
|---|---|---|---|
| Domain Shield | DNS security + malware scan | $0.12 | VirusTotal (70+ engines) |
| Company X-Ray | Firmographics + tech stack | $0.15 | People Data Labs |
| Threat Pulse | IP/domain threat intel | $0.10 | VirusTotal + AbuseIPDB |
| Prospect IQ | Sales intel + email contacts | $0.12 | Hunter.io |
| Compliance Check | IT compliance audit | $0.15 | Qualys SSL Labs |
| Health Signal | Drug info + interactions | $0.10 | NIH RxNorm + FDA |
| Property Intel | Location + demographics | $0.10 | US Census + OpenWeather |
| Sports Edge | Pre-game AI analysis | $0.12 | The Odds API + Claude AI |
All endpoints powered by Alderpost Intelligence.
How Payment Works
You ask Claude a question
→ Claude calls x402_research or x402_call
→ This MCP calls AgentCash CLI
→ AgentCash signs a USDC payment on Base
→ The endpoint verifies + settles on-chain
→ Data returned to Claude
→ Claude answers your question
You fund AgentCash once. Every x402 call draws from that balance. No subscriptions. No API keys. Pay for exactly what you use.
Example Session
You: "Tell me everything about hubspot.com"
Claude: I'll run a comprehensive research scan on hubspot.com.
[Calls x402_research with subject "hubspot.com"]
Results from 5 endpoints ($0.64 total):
Domain Shield: Security score 85/100. DMARC=reject, SPF=pass,
DKIM configured. VirusTotal: clean (0/94 engines flagged).
Company X-Ray: HubSpot, Inc. Founded 2006. 10,268 employees.
Computer Software. Cambridge, MA. Public company.
Tech: Cloudflare CDN, Google Workspace, Next.js.
Threat Pulse: Threat score 92/100. No blacklist hits.
AbuseIPDB: 0 reports. Clean reputation.
Compliance Check: SSL Labs grade A. 6/6 security headers.
DNSSEC not enabled. Cookie consent detected.
Prospect IQ: Prospect score 82/100 (hot). 5 verified email
contacts found via Hunter.io. Email pattern: {first}@hubspot.com.
Pricing
This MCP server is free. You only pay for the x402 endpoints you call. Typical costs:
- Single endpoint call: $0.10 - $0.15
- Full domain research (5 endpoints): ~$0.64
- Health/property/sports query: ~$0.10
$5 in AgentCash covers approximately 40 individual calls or 8 full research reports.
Why This Exists
The x402 protocol is designed for agents to pay for data autonomously. But the ecosystem has a cold-start problem: sellers have built endpoints, but there aren't enough buyers calling them. This MCP is the buyer-side infrastructure that makes x402 work as intended.
Every install creates a new buyer in the x402 economy. Every research call generates 3-5 real on-chain transactions. This is how the agent economy bootstraps.
Links
- Alderpost Intelligence — Endpoint provider
- AgentCash — Wallet & payment infrastructure
- x402scan — Ecosystem explorer
- x402 Protocol — Protocol specification
License
MIT — Alderpost LLC, Wisconsin