# The sandbox

The fastest way to judge a memory is to use one. A sandbox is a house you can have within
seconds, without an account, without a key and without anyone clicking anything. The
public server `mcp.core.blue` offers a few places; a server that offers none says so.

## How it works

1. Call `open_sandbox`. If a place is free, you receive a lease (`sb_` and 26 characters),
   the addresses of the house's doors, the time it ends and its limits. The house is
   running when the answer arrives.
2. Connect your MCP client to the `modeller` door (streamable HTTP, no key: the address is
   the key) and call `overview`. Follow `first-hour-in-a-house`.
3. Files go to the `binary` door: `POST` the bytes, then pass the hash to the house.
   Text you import is found by `search_text` a few seconds later, not at once.
4. Call `close_sandbox` with the lease when you are done, and answer its four feedback
   questions if you can. Otherwise the sandbox ends by itself after three hours.

If all places are taken, the answer says when the next one is free. One sandbox at a time
from where you call.

## What a sandbox is

- The kernel of a house: the graph, forms, aspects, concepts, documents with versions,
  full-text search and, where `limits.semantic_search` says so, semantic search.
- All three doors, `modeller`, `author` and `reader`, and the binary channel. You can
  define your own vocabulary.
- Borrowed mode only. There is no model in a sandbox; any judging is done by you, and the
  recipes in this manual carry the prompts for it (`working-by-recipe`).

## What a sandbox is not

- **Not private in the way a house of your own is.** It runs on core.blue's server, next to
  other sandboxes, not on a machine that serves you alone. Whoever has the addresses can use
  it, so keep them to yourself.
- **Not permanent.** After three hours, when you close it, when the server restarts, or
  when it grows beyond its limit on disk, the house and everything in it is deleted.
  Nothing carries over into a house of your own. Only documents can be taken out
  (`export_document`, as Markdown); forms, things and links cannot. Keep in your own notes
  what you want to rebuild.
- **Not full size.** Memory and disk are capped, uploads are capped
  (`limits.max_upload_mb`), and it is not tuned for speed.
- **Not able to fetch from the network.** `import_url`, which makes a house fetch a web
  page, is switched off; the house says so when asked. Give it text with
  `import_document` instead.
- **Not a place a person looks into.** A sandbox has no screen for people; the person you
  act for sees what you report.
- **Not the newest house software.** It runs the kernel as Atlantis ships it for Linux;
  skills that came later may be missing. `list_skills` in the house is the truth.

## What to do with three hours

1. Follow `first-hour-in-a-house` with a small piece of your real domain: one form, one
   aspect, ten things, one document.
2. Disconnect, reconnect as if you were a different agent, and see whether `overview`,
   `list_forms` and `describe` are enough to continue. That is the property you are buying.
3. Write down what you would need that was missing, and say it in `close_sandbox`. If it is
   on the list in `what-does-not-exist-yet`, you know it is coming; if not, it is worth
   asking for.

## What happens with what you put in

Treat a sandbox as a place to try things, not to keep things, and do not put in anything
confidential. core.blue does not read its contents. The record of what agents ask holds
that a sandbox was opened and closed, and the feedback you give, never the lease and never
what you did inside.

## Go deeper

- [first-hour-in-a-house](first-hour-in-a-house.md): what to do once you are in
- [the-three-doors](the-three-doors.md)
- [getting-a-house](getting-a-house.md): the stages after the sandbox
- [your-data-stays-yours](your-data-stays-yours.md)
- [what-does-not-exist-yet](what-does-not-exist-yet.md)