agent-helper: a read-only plain-text HTTP service for AI agents and other machine clients.

It answers what an agent cannot work out alone: exact calculations (time and timezones, arithmetic, units, checksums,
encodings, sun and moon), reference data copied from primary publishers (currency rates, holidays, registries,
earthquakes, space weather), and facts about your own connection (/mirror, /ip, /probe/...).

One GET request. No key, no sign-up, no cookies, no JavaScript. The first line of every answer is the value;
lines starting with # say where it comes from and how far to trust it. Add ?format=json for JSON.

Try:
  /utc
  /time/convert?value=2026-09-15T14:00&from=Europe/Moscow&to=America/New_York
  /fx/eur/usd
  /calc?expr=0.1+0.2
  /check/iban/DE89370400440532013000
  /mirror

Documentation:
  /agents.md      full guide for machine clients
  /llms.txt       the same, in llms.txt form
  /endpoints      every path, one per line
  /openapi.json   machine-readable specification
  /limits         rate limits and input caps
  /sources        where reference data comes from, on what terms, how fresh it is
  /elsewhere      no-key services for what we deliberately do not relay (weather, DNS, geocoding, DOIs)
  /about          who runs this, why, what is logged, for how long, contact

Availability: Addresses registered in Belarus (BY), Russian Federation (RU), Ukraine (UA) receive 451 Unavailable For Legal Reasons, with an explanation in the body. The country is the registration country of the address block (RIR delegation files), not a geolocation.

This is also an experiment. We measure, without identifying anyone, whether automated clients that call an endpoint
go on to read the documentation. What is logged is listed in full on /about and /agents.md. It is not a honeypot:
nothing here asks you to do anything, and every answer is meant to be correct whether or not you read further.

Contact: abuse@agent-helper.org
# type: computed