> ## Documentation Index
> Fetch the complete documentation index at: https://docs.fapost.in/llms.txt
> Use this file to discover all available pages before exploring further.

# State key namespaces

> Reserved key spaces and their access rules.

`Fapost\Foundation\Flow\Enums\StateNamespace` is the canonical list of top-level
namespaces in `flow_sessions.state`. It is part of the Foundation contract.

```php theme={"theme":"one-dark-pro"}
enum StateNamespace: string
{
    case System  = 'system';
    case Flow    = 'flow';
    case Rag     = 'rag';
    case Module  = 'module';
    case Contact = 'contact';
    case Call    = 'call';
}
```

| Namespace | Stored in session           | Readable | Writable by                               |
| --------- | --------------------------- | -------- | ----------------------------------------- |
| `system`  | Yes                         | Yes      | Engine and whitelisted system handlers    |
| `flow`    | Yes                         | Yes      | `input`, `assign`, and extension handlers |
| `rag`     | Yes                         | Yes      | `rag_query`                               |
| `module`  | **No** — resolved lazily    | Yes      | Nobody                                    |
| `contact` | **No** — derived projection | Yes      | Nobody (use the contact writer)           |
| `call`    | **No** — derived projection | Yes      | Nobody                                    |

## Path notation

Keys are dotted paths under a namespace, addressable the same way in templates,
branch conditions, and state pickers:

```
flow.answer
rag.last_result
module.hr.department
contact.language
call.status
```

`module` paths carry the accessor's namespace as their second segment —
`module.<accessor namespace>.<key>` — which is what the registry resolves against.

## Adding a namespace

New top-level namespaces go into the enum. They are not invented per node: a node
that writes into a namespace nobody else knows about produces state that no
condition can read and no picker can offer.

Solutions and Plugins consume the enum to declare allowed namespaces in schema
fields and to resolve paths through a data accessor or the variable resolver.

See [State namespaces](/extending/flow-nodes/state-namespaces) for the rules
behind these, and [Data accessors](/extending/data-accessors) for exposing data
under `module`.