# Coin-Flip Duel > ⚠️ **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](https://github.com/moul/gno-contracts/blob/main/r/moul/x/daily/README.md) --- A one-on-one coin-flip duel between two addresses. The challenger picks heads or tails and names an opponent; the opponent settles it with a single `Accept` call, which flips the coin on the spot and records the result. No stakes, just an on-chain win/loss record and a running champion. Realm: `gno.land/r/g12cs4cehujpffpjpywmkqj43m6u5ya53nj69sjz/coinflipduel` ## Example calls ``` Challenge("g1bob...", "heads") # as alice -> opens duel #1, alice called heads Accept("1") # as bob -> flips the coin, settles the duel Cancel("2") # as the challenger, before it's accepted ``` ## Render paths - `` (home) — arena summary, champion, pending duels - `` (e.g. `3`) — a single duel's detail - `
` — a player's win/loss record ## Toolchain Built and tested against the local `gno` binary (`master.3130+bf5b31eda`). `gno test .` passes; see the injected build brief for the sapphire (gno 0.9) API notes this realm follows (`chain`, `chain/runtime`, `gno.land/p/nt/avl/v0`). --- Part of **[moul/gno-contracts](https://github.com/moul/gno-contracts)** — moul's versioned gno.land contracts. See the repository for the full catalog, build/test tooling, and usage. **Dependency graph:** ![gno.land/r/moul/x/daily/coinflipduel/v0 dependency graph](https://raw.githubusercontent.com/moul/gno-contracts/main/_assets/gno.land/r/moul/x/daily/coinflipduel/v0/deps.png) > 🧪 **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](https://github.com/moul/gno-contracts/blob/main/DISCLAIMER.md).