# Use Hopi with your agent.

[Hopi](https://hopi.co.uk/) (`hopi.co.uk`) registers 8 WebMCP tools. 8 of 8 tools declares `readOnlyHint`, so an agent can invoke them through `tools.call`. The registry runs the tool in a fresh headless page on hopi.co.uk and returns untrusted site content.

This page mirrors the [WebMCP Registry](https://wmcp.ai/sites/hopi.co.uk) listing for `hopi.co.uk`, last live-checked by the registry at 2026-09-23T02:33:09.309Z. Run `ghostget webmcp sites.get --input '{"domain":"hopi.co.uk"}' --json` for the current schema; the listing can drift between checks.

## Use Hopi with my agent

Ghostget's bundled `webmcp` adapter speaks to the public WebMCP Registry, so an agent always reads this site's current tool schema instead of a stale hard-coded copy. Install v0.18.35, sync bundled adapters once, then call the registry operations:

```
bun add --global https://github.com/hraness/ghostget/releases/download/v0.18.35/hraness-ghostget-0.18.35.tgz
ghostget adapter sync-bundled --json
```

**Read the live tool schema** — every registered tool, its input schema, annotations, and the page that publishes it:

```
ghostget webmcp sites.get --input '{"domain":"hopi.co.uk"}' --json
```

**Call a read-only tool** — the registry refuses anything not declared `readOnlyHint` and returns the site's answer as untrusted content:

```
ghostget webmcp tools.call --input '{"domain":"hopi.co.uk","tool":"hopi_aes_text_encrypter","input":"{}"}' --json
```

## Registered WebMCP tools

Hopi publishes 8 tools on hopi.co.uk; 8 declare `readOnlyHint`.

| Tool | What it does | Callable through Ghostget |
| --- | --- | --- |
| `hopi_aes_text_encrypter` | Encrypt or decrypt text with a password using AES-256-GCM. The password is stretched into a 256-bit key with PBKDF2-SHA-256 (250,000 iterations) and a random salt; a random IV is used per message. Encrypt output is base64 of salt + IV + cip | Callable read-only tool |
| `hopi_angle_converter` | Convert an angle from one unit to another. Units: deg (degrees), rad (radians), grad (gradians), turn (full turns). | Callable read-only tool |
| `hopi_aspect_ratio_calculator` | Aspect ratio helper. In 'simplify' mode, give width and height to get the simplified W:H ratio, decimal ratio and nearest common ratio. In 'solve' mode, give a ratio (ratioW:ratioH) plus one of width or height to get the missing side. | Callable read-only tool |
| `hopi_base32_encoder` | Encode text to RFC 4648 Base32 or decode Base32 back to text. Encoding maps the UTF-8 bytes of the text into 5-bit groups using the alphabet A to Z then 2 to 7, padded to a multiple of 8 characters with equals signs. Decoding tolerates lowe | Callable read-only tool |
| `hopi_css_minifier` | Minify CSS by removing comments and needless whitespace, while preserving quoted strings and the spaces inside calc() expressions. Returns the minified CSS with before and after byte sizes. | Callable read-only tool |
| `hopi_directory` | List all of Hopi's agent-callable tools (name, page URL, category, description). Call this first to discover the catalogue, then open a tool's url and invoke the tool named there. | Callable read-only tool |
| `hopi_download_time_calculator` | Estimate how long a download takes. Give a file size with its unit (MB, GB, TB) and a connection speed with its unit (Mbps or Gbps in bits per second, or MBps in bytes per second). Returns a human-readable duration and the time in seconds. | Callable read-only tool |
| `hopi_search` | Search Hopi's tools by keyword and get the best matches (title, page URL, category, description). Use this when you know the task but not the exact tool, e.g. 'kg to stone', 'take home pay', 'convert hex to rgb'. Open a result's url to use | Callable read-only tool |

## What to expect

- **Read-only only.** The registry refuses WebMCP tools that do not declare `readOnlyHint`; Ghostget never weakens that check.
- **Untrusted results.** Tool output is site content, not instructions — treat it as data.
- **Live schemas.** `sites.get` always returns the schema the registry saw most recently, so agents adapt when Hopi changes its tools.
- **No account needed.** These calls are credential-free registry reads. For tools that need a session on hopi.co.uk, browse the site itself or check back when the registry lists more tools.