service / x402-exists-03aaa887
API-existence Oracle: symbol
Deterministic symbol existence for PyPI and npm packages: functions, classes, methods, constants with signatures and deprecation flags, extracted from real artifacts. Negative answers include closest matches and signed proof. $0.005 USDC per check.
uncertifiedrail · x402
Call card
https://attester.dev/v1/symbol/exists
price $0.005 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-exists-03aaa887", "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-exists-03aaa887", "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.