@melis-ai/x402-tools-mcp

Boring infrastructure for agent builders. 16 pay-per-call utility tools served as an MCP server — scrape, validate, notify, convert, synthesise. No subscriptions, no API keys. Pay with USDC on Base via the x402 protocol.

npx @melis-ai/x402-tools-mcp

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Tool catalogue

Tool	Price (USDC)	Description
list_services	free	Returns the full catalogue with prices and endpoint URLs
cacheserve	$0.001	Fetch a URL with caching — returns cached version if recent
docconvert_text	$0.001	Format conversion: md↔html, json↔csv, etc.
docconvert_pdf	$0.005	Convert HTML or markdown to PDF (base64 output)
linkrisk	$0.005	Lightweight URL risk profile: phishing signals, domain age, IP reputation
linksafe	$0.01	Definitive URL safety check via Playwright sandbox + VirusTotal
markdownopt	$0.005	Convert URL or HTML to clean LLM-ready markdown (~70% token reduction)
notifyrelay_email	$0.005	Send a transactional email (allowlisted domains, rate-limited)
notifyrelay_telegram	$0.002	Send a Telegram message to a known chat ID
notifyrelay_webhook	$0.001	POST a JSON payload to a URL with optional HMAC signing
promptguard	$0.002	Score untrusted input for prompt injection risk (0–100)
schemagate	$0.001	Validate LLM output against a JSON Schema
scrapepay	$0.01	Web extraction via Playwright (robots.txt enforced, SSRF-safe)
structextract	$0.002	Extract structured JSON from HTML (tables, links, emails, phones…)
web_synthesise	$0.05	Multi-source web research with synthesised answer + citations
screenshot	$0.02	Headless Chromium PNG screenshot of any public URL
pdf_render	$0.49	High-fidelity URL or HTML to PDF via Playwright

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Installation — Claude Desktop

Add to your claude_desktop_config.json:

{
  "mcpServers": {
    "x402-tools": {
      "command": "npx",
      "args": ["@melis-ai/x402-tools-mcp"],
      "env": {
        "X402_PAYMENT_HEADER": "your-signed-payment-token",
        "X402_INTERNAL_KEY": "your-internal-key-if-issued"
      }
    }
  }
}

Config file locations:

• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
• Windows: %APPDATA%\Claude\claude_desktop_config.json

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Payment — how x402 works

These tools use the x402 protocol for pay-per-call billing in USDC on Base.

When a tool call requires payment, the service returns HTTP 402 with a signed payment quote. Your x402-enabled MCP client (or wallet integration) signs the payment and retries the request with an x-payment header.

Environment variables:

Variable	Purpose
X402_PAYMENT_HEADER	Signed x402 payment token from your wallet client. Set this if you're handling payments manually or testing with a pre-signed token.
X402_INTERNAL_KEY	Bypass key issued to trusted internal callers (melis.ai customers). Skips the 402 flow entirely for allowlisted keys.

If neither variable is set, calling a tool will return a 402 error with the payment quote so your client can handle it.

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Composition example

A common agent pattern — scrape a page, clean it for LLM consumption, guard the prompt, process:

1. scrapepay      → fetch raw HTML from target URL          ($0.01)
2. markdownopt    → convert HTML to clean markdown          ($0.005)
3. promptguard    → score the scraped content for injection ($0.002)
4. → pass clean markdown to your LLM

Total cost per run: ~$0.017 USDC. No API keys, no rate limit accounts, no monthly bills.

Another pattern — validate LLM output before acting on it:

1. Your LLM       → produce a JSON response
2. schemagate     → validate response matches your schema   ($0.001)
3. → act on validated data, or retry if invalid

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Architecture

This is a stdio MCP server. Your MCP client (Claude Desktop, Cursor, or any MCP-compatible runtime) spawns it as a subprocess and communicates over stdin/stdout. No network port, no daemon, no config service.

Each tool call makes one outbound HTTPS request to the corresponding melis.ai microservice. The MCP server itself is stateless.

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MIT Licence

Copyright 2026 Sean Melis

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.