# `ModelId`

An AI model by its provider and name: `openai/gpt-4o`.

Use it to record which model made an answer or an [`Embedding`](/docs/types/type-embedding.md).

## Shape

| Field | Type | Required? |
|---|---|---|
| `provider` | `Text` | Yes |
| `name` | `Text` | Yes |

## Example

```jadpo
ModelId { provider: "openai" name: "gpt-4o" }
```

`text.parse(raw, as: ModelId)` reads one from text that comes from outside. Text that isn't one at all fails `malformed`, such as `gpt-4o`, `openai/` or `/gpt-4o`.

## Good to know

- As text it needs its provider, so `gpt-4o` alone is refused.
- A model an app calls comes from a `ModelId` setting rather than a name in the code, so changing it is a reviewed change.
- `==` tells you whether two are the same. `<` and `list.sort_by` don't take it, so sort by one of its parts instead.

## In JSON

A string, in a request, a response or `json.write`:

```json
"openai/gpt-4o"
"meta-llama/Llama-3.1-8B-Instruct"
"ollama/llama3:8b"
```

## Details

<details>
<summary>Text form, storage, how it is shown, and operations</summary>

`ModelId` is in the group Other with a published standard, and has been in Jadpo since 0.1.0.

### Text form

`text.from` writes one standard text form, the same form `text.parse` reads back: `openai/gpt-4o`, `meta-llama/Llama-3.1-8B-Instruct` and `ollama/llama3:8b`.

### How it is stored

It is stored in 2 columns, each named for the field, `_` and its suffix. This is `meta-llama/Llama-3.1-8B-Instruct`:

| Column | Type | Holds |
|---|---|---|
| `<field>_provider` | `text` | `'meta-llama'` |
| `<field>_name` | `text` | `'Llama-3.1-8B-Instruct'` |

### How it is shown to people

`text.format(value, locale:)` shows it to people in their locale.

With `locale: Locale.en_gb`:

| Value | Shown |
|---|---|
| `openai/gpt-4o` | `openai/gpt-4o` |
| `meta-llama/Llama-3.1-8B-Instruct` | `meta-llama/Llama-3.1-8B-Instruct` |
| `ollama/llama3:8b` | `ollama/llama3:8b` |

### Operations

It also takes `text.parse`, `text.from`, `text.format`, `json.read`, `json.write` and `==`. [How every standard type behaves](/docs/every-standard-type-meets-one-contract.md) says how they work.

</details>