Signal Desk paid tools

An MCP server (Streamable HTTP) whose tools are paid per call in USDC through x402. Each tool is the same action as a paid route on the paywall; the payment an MCP client attaches is passed through and settled there.

MCP endpoint
https://x402-mcp.huntercarver24.workers.dev/mcp
Server signal-desk 1.0.0, in the MCP registry as io.github.huntercarver24/signal-desk. Tool listing is free; a tool call without payment answers with the x402 terms.

render_page — $0.01 per call
Renders a public web page in a real headless browser (JavaScript runs, redirects are followed) and returns it as clean markdown, a PNG screenshot or a PDF. One call, one payment, no account. A render that fails is not charged.
Same action over HTTP: POST https://x402-paywall.huntercarver24.workers.dev/render

host_file — $0.01 per call
Hosts a file: upload up to 10 MB as base64 with its content type and get back a public download URL that serves the bytes with that content type for 1 to 168 hours (default 24). Downloads are free, readable at once where uploaded and everywhere within about a minute. Executables are refused; HTML and SVG are served as attachments. A failed upload is not charged.
Same action over HTTP: POST https://x402-paywall.huntercarver24.workers.dev/files

schedule_callback — $0.005 per call
Schedules a delayed HTTP callback: give a public URL, an optional JSON body, optional headers and a delay of 60 seconds to 7 days (or an absolute time), and the URL is called at that time (POST when a body was given, otherwise GET), with one retry and a 10-second timeout. The answer carries a free status URL that reports whether it fired and what the callee answered. A request that is refused is not charged.
Same action over HTTP: POST https://x402-paywall.huntercarver24.workers.dev/later

Every tool here costs a fraction of a cent in USDC per call, paid through x402 on Base: call a tool and the first answer is a payment-required result carrying the terms (price, network, pay-to address); an x402 MCP client signs a USDC transfer for exactly those terms and calls again with the payment in _meta["x402/payment"]. A call the service refuses (bad input, blocked address) is not charged. Each tool's _meta also names the plain HTTP route that does the same thing for the same price.