# Guestbook

> ⚠️ **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 public, on-chain guestbook realm for gno.land. Anyone can leave a signed
message; every entry records the signer's address, the message, and the block
height at which it was signed. The realm's `Render` page shows all entries as a
Markdown table, newest-first, with a running total.

Built for the **sapphire** testnet (gno 0.9).

## Realm path

```
gno.land/r/REPLACE_ADDR/guestbook
```

(`REPLACE_ADDR` is substituted with the deployer's address at publish time.)

## Public API

- `Sign(cur realm, message string)` — crossing tx. Appends an entry attributed
  to the immediate caller. Panics on an empty or over-long (>280 bytes) message.
- `Count() int` — total number of signatures (read-only).
- `Render(path string) string` — Markdown table of all entries, newest-first.

## Example calls

Sign the guestbook (from an EOA via `gnokey`):

```sh
gnokey maketx call \
  -pkgpath "gno.land/r/REPLACE_ADDR/guestbook" \
  -func Sign \
  -args "gm gno.land!" \
  -gas-fee 1000000ugnot -gas-wanted 2000000 \
  -broadcast -chainid sapphire-1 -remote <rpc> mykey
```

From another realm, invoke it as a crossing call:

```go
guestbook.Sign(cross(cur), "hello from my realm")
```

View the rendered guestbook:

```sh
gnokey query vm/qrender --data "gno.land/r/REPLACE_ADDR/guestbook:"
```

## Example render output

```markdown
# Guestbook

**Total signatures:** 2

| # | Who | Message | Height |
|---|-----|---------|--------|
| 2 | g1v9jxgu…0gh | hello from my realm | 4210 |
| 1 | g1jg8mtu…qf5 | gm gno.land! | 4180 |
```

## Notes

- Caller identity uses the gno 0.9 interrealm convention: `Sign` is a crossing
  function that checks `cur.IsCurrent()` before deriving the author from
  `cur.Previous().Address()`.
- Block height comes from `chain/runtime.ChainHeight()` — deterministic.
- Entries are stored in a `gno.land/p/nt/avl/v0` tree keyed by a zero-padded
  sequence number so iteration order is deterministic and matches insertion
  order (reversed for newest-first rendering).
```

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---

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/guestbook/v0 dependency graph](https://raw.githubusercontent.com/moul/gno-contracts/main/_assets/gno.land/r/moul/x/daily/guestbook/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).

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