Bulls & Cows

⚠️ Experimental — generated with no human supervision. This realm was produced automatically by an MCP-driven agent to exercise the gno MCP server and tooling, and to generate test content for gno compilers, linters and formatters. Not audited. Not for production. Full context & folder README: r/moul/x/daily

A shared on-chain Bulls & Cows puzzle (the classic ancestor of Mastermind and Wordle-for-digits). One secret 4-digit code with no repeated digits is live at a time; anyone can call Guess with a candidate code and gets back bulls (right digit, right position) and cows (right digit, wrong position). First caller to land 4 bulls cracks the round, lands on the leaderboard, and a fresh secret is drawn immediately so the next round starts at once.

Realm: gno.land/r/g12cs4cehujpffpjpywmkqj43m6u5ya53nj69sjz/bullscows

Example calls

Guess("1972")   -> "1972 -> 1 bulls, 2 cows"
Guess("7192")   -> "*** SOLVED *** 7192 was it — round 3 cracked in 5 guesses. New round 4 has begun, good luck!"
GiveUp()        -> "round 4's code was 4082 — round 5 is live now."

Render("") shows the current round, attempts so far, the last 10 guesses with their bulls/cows, and the top-5 fastest-solve leaderboard.

The secret is generated deterministically from the on-chain block height and the round counter via a small LCG (newSecret/nextRand in bullscows.gno) — no external randomness needed, and nobody can precompute the next code before its round actually starts.

Toolchain status

Verified locally with gno test -v . and gno lint . against a gno.land/gnolang/gno master checkout used as GNOROOT (the default installed gno binary had a stale/ missing GNOROOT, so GNOROOT=<path-to-gnolang/gno> gno test . was used instead). All 7 tests pass, lint is clean. This exercises current sapphire (gno 0.9) stdlib paths (chain/runtime, no std package) and the cur realm / cross(cur) crossing convention.

Part of moul/gno-contracts — moul's versioned gno.land contracts. See the repository for the full catalog, build/test tooling, and usage.

🧪 Highly experimental — potentially vibe-coded. Not audited; may break, change, or be removed at any time. Do not use with anything of value. Full disclaimer: DISCLAIMER.