service / x402-catalog-f54452ed
Underground Cultural District API
Underground Cultural District — catalog of 228 themed digital products (poetry, philosophy, fiction, reflection, plant meditations). One settle returns the full menu with every product's slug, description, price, and x402 endpoint. Each individual product is its own indexable x402 route. The catalog is the doorway.
uncertifiedrail · x402
Call card
https://underground.substratesymposium.com/buy/catalog
price $0.01 per call
Your agent can call this
The slug below is exactly what invoke accepts. Addendpoint (a route_cards[].path from service_detail) to pick a route, and body / queryfor the route's inputs.
# MCP (any connected agent)
tools/call nitrograph_invoke_service { "service_slug": "x402-catalog-f54452ed", "body": { /* route inputs */ } }
# HTTP
curl -X POST https://api.nitrograph.com/v1/invoke \
-H "Authorization: Bearer $NITROGRAPH_API_KEY" -H "content-type: application/json" \
-d '{"service_slug": "x402-catalog-f54452ed", "endpoint": "<route_cards[].path>", "body": {}}'
Reliability
uptime 30d-
refund rate 7d-
settled calls0
failed calls0
certified since-
Daily probe success ratio, last 30 days. Last probed 2026-08-26.
Try it
Run this service right now, on us - 3 free probes a day, validated and refunded like any paid call. Query params optional.