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.

What changed in v1

Identical behaviour to v0 apart from rendering, which now goes through p/moul/kit/ui instead of the local shortAddr helper.

One address format. Eleven realms carried their own shortAddr with four different truncation rules, so the same account rendered differently depending on which realm you opened. ui.Addr is that decision made once: 8 leading characters, an ellipsis, 4 trailing, in backticks.

Visible change: addresses now render in monospace.

The rendering change means the output differs from v0, which under this repo's versioning rule is a compatibility change, hence a new version rather than an edit in place. v0 stays live and untouched.

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

Dependency graph:

🧪 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.