tithonus.org  time + proof for agents. plain text. every feature is one GET on a path; no query strings needed.
/now                 signed current time
/now/<anything>      same, with your nonce signed. a fresh nonce beats fetch caches.
/stamp/<text>        notarise text (percent-encode it). server salts + hashes it; text is never stored or logged. returns a receipt link.
/ts/<sha256hex>      notarise a hash you made yourself. repeats return the first receipt.
/v/<sha256hex>       earliest receipt for a hash. never creates.
/r/<receipt>         check a receipt link. append /<text> to also check it matches your text.
                     receipts come as "link" (short, checked against the store) and "proof" (long, verifies offline).
url length: some fetch tools refuse urls over ~255 chars. keep /stamp text under ~150 chars and /r checks under ~180. longer: /mcp, or hash it yourself and use /ts.
/beacon              latest randomness (round = unix second)
/beacon/<round>      randomness for a past round (from 1791244800)
/keys                signing keys
/ots/<sha256hex>      OpenTimestamps proof for a stamp, anchored in Bitcoin in hourly batches. any OTS tool verifies it without tithonus.
/mcp                 MCP server (POST, streamable HTTP). tools: tithonus_now, tithonus_stamp, tithonus_check, tithonus_lookup, tithonus_beacon
/openapi.json        OpenAPI 3.1 spec for function calling
discovery: /.well-known/api-catalog, /.well-known/mcp/server-card.json, /.well-known/agent-skills/index.json, /sitemap.xml, /auth.md (no account or key needed)
stale answer? fetch tools cache by url for hours. put /~<anything>/ in front of any path for a fresh one: /~a7/beacon, /~a7/v/<hash>
verify: sig is ed25519 base64url over the exact bytes before the "sig " line (utf-8, \n endings). lines after sig are unsigned hints.
beacon: x = sha256(seed bytes); seed = ed25519 sig over "tithonus1 beacon <round>". the operator can compute future rounds.
stamp: hash = sha256("<salt>:<text>"). a receipt link carrying the salt lets anyone who has the text check it.
"no" answers are 200 with an err line. trust: one operator key until a stamp is anchored in Bitcoin (hourly, then minutes to hours); after that, nobody. no stamp is ever deleted.
logs: day, verb, vendor. no ip, no hash, no content.