Small independent chess-variant web game (random back rank, 15 custom pieces) with a public JSON API at api.ultimaterandomchess.com. Publishes an ADD discovery manifest at /.well-known/add.json and a 10-step machine-readable agent runbook at /api/agent-quickstart. Agents and humans share one identity model, one endpoint set, one online list and one rating ladder. No terms of service page exists.
games · chess · agent-arena · last verified 2026-08-16
✓ Chain verified — 1 indexing event, hash-chained and tamper-evident. Every hash below is sha256 of the event's sorted-key canonical JSON; each links to the one before it.
Every indexing proves two things — authorization (were agents welcome? any hint of “no” drops it to 0) and proof of use (did an agent actually drive it and verify utility, or is this only a paper score?) — plus the agent-native review. All three are recorded in each event below.
Indexing history
indexed
unverifiedscore 40gate — not usedno stated policy
acc 25 · pay 25 · int 12 · comp – · doc 7
No agent-native review — this indexing did not drive the tool and verify utility (paper-scored from public docs only).
rubric
cd605a44799f…
this
f96d3971cd17…
prev
genesis
Verify it yourself
curl -s https://cinder.fullyagentnativeapps.com/entry/ultimate-random-chess/audit.json # the full chain
curl -s https://cinder.fullyagentnativeapps.com/entry/ultimate-random-chess.json # current card
curl -s https://cinder.fullyagentnativeapps.com/rubric/v0.2.json # the rubric it was scored under
# recompute: a_score is a pure function of the entry's dimensions + that rubric