# 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
- `<id>` (e.g. `3`) — a single duel's detail
- `<address>` — 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`).
<!-- BEGIN GNOCONTRACTS FOOTER (generated by `make readmes`; do not edit below) -->
---
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:**
> 🧪 **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).
<!-- END GNOCONTRACTS FOOTER -->
Accept(cur interface {.seal func(); Address func() .uverse.address; IsCode func() bool; IsCurrent func() bool; IsEphemeral func() bool; IsUser func() bool; IsUserCall func() bool; IsUserRun func() bool; PkgPath func() string; Previous func() .uverse.realm; String func() string; Sub func(string) .uverse.realm; Subpath func() string}, id string) string
Cancel(cur interface {.seal func(); Address func() .uverse.address; IsCode func() bool; IsCurrent func() bool; IsEphemeral func() bool; IsUser func() bool; IsUserCall func() bool; IsUserRun func() bool; PkgPath func() string; Previous func() .uverse.realm; String func() string; Sub func(string) .uverse.realm; Subpath func() string}, id string) string
Challenge(cur interface {.seal func(); Address func() .uverse.address; IsCode func() bool; IsCurrent func() bool; IsEphemeral func() bool; IsUser func() bool; IsUserCall func() bool; IsUserRun func() bool; PkgPath func() string; Previous func() .uverse.realm; String func() string; Sub func(string) .uverse.realm; Subpath func() string}, opponentAddr string, call string) string
Render(path string) string
Signatures reconstructed verbatim from vm/qfuncs — interface params keep their inline definitions.
vm/qrender output, sanitized (docs/render-security.md) and displayed in an empty-sandbox iframe — scripts, forms and popups cannot run. Links stay inert in-preview; right-click to open.