# Licensing

A licence covers **the house as a machine**. Whoever is in the house is in the house: there
are no seats, no per-user fees, no per-call fees. A house with one person and one agent
costs the same as the same house with ten people and fifty agents.

## What you choose

| Axis | Choices | What it changes |
|---|---|---|
| **Size** | `economy`, `premium`, `on-premise` | the machine and the local computation it carries; see `sizes-and-volumes` |
| **Data volume** | additional volumes attached to a VM house | how much the house can hold |

The doors (reader, author, modeller) are not tiers. Every house has all three, and a
licence covers all three.

## What is metered and what is not

- **Not metered:** calls, skills used, number of agents, number of people, number of keys.
- **Metered, optional and planned:** a model service operated by core.blue, at the
  provider's token price plus a service fee. If you attach your own model or your own API key,
  core.blue meters nothing. See `plugging-in-a-model`.

## When a licence expires

The house becomes **read-only**. The reader door keeps working; writes are refused with a
message that says why. Nothing is deleted, nothing is locked away, export keeps working.
A licence cannot be revoked; one that should end early is replaced by one with a shorter
period.

## The licence file

A house on a core.blue VM is licensed by its subscription. A house on your own hardware
carries a small signed JSON document, conventionally `license.json`:

| Field | Meaning |
|---|---|
| `format` | format version, 1 |
| `house` | the house id, stable even if the house moves |
| `licensee` | who holds the licence |
| `issuedOn`, `validUntil` | the period, both days inclusive |
| `edition` | `economy`, `premium` or `on-premise` |
| `issuer` | `core.blue` |

The signature is ECDSA over P-256 with SHA-256, over a canonical form of these seven
fields. The house verifies it with core.blue's public key and never has to call home,
which is what makes `on-premise` possible in networks without internet access. Renewing
means placing a new file. The licence does not limit how much data an `on-premise` house
holds.

The format is specified so that it can be verified independently: a written specification
and a set of test vectors exist, and a reader written from the specification alone, in
another language, gives the same verdicts as core.blue's own. Reading the licence inside a
house is planned; the house does not check one yet.

## Prices

Call `pricing`: it returns the offer as data. A licence costs what the house costs; there
is no separate price for the licence file. The price of `on-premise` is not yet decided.
The terms are part of the same data: no minimum term, and a subscription ends with the
month that is paid.

## Go deeper

- [sizes-and-volumes](sizes-and-volumes.md)
- [getting-a-house](getting-a-house.md)
- [your-data-stays-yours](your-data-stays-yours.md)
- [plugging-in-a-model](plugging-in-a-model.md)