{
    "$schema": "https://json-schema.org/draft/2020-12/schema",
    "$id": "https://schemas.plurnk.dev/v0/SchemeRegistration.json",
    "title": "SchemeRegistration",
    "description": "A scheme entry in the agent's scheme registry. Defines what `<name>://` resolves to and how it's accessible.",
    "type": "object",
    "required": ["name", "model_visible", "category", "default_scope", "default_channel", "writable_by", "volatile", "handler"],
    "additionalProperties": false,
    "properties": {
        "name": {
            "type": "string",
            "pattern": "^[a-z][a-z0-9+.\\-]*$",
            "description": "Scheme name without `://`. Matches the URL scheme character class."
        },
        "model_visible": { "type": "boolean" },
        "category": { "type": "string", "minLength": 1 },
        "default_scope": { "enum": ["workspace", "worker"] },
        "default_channel": {
            "type": "string",
            "pattern": "^[a-z][a-z0-9_-]*$",
            "description": "Channel name selected when an op against this scheme has no fragment. Conventionally `body`; executor schemes (`{tag}://`) typically declare `stdout`."
        },
        "channel_orientations": {
            "type": "object",
            "description": "Per-channel content-orientation hints. `head` = whole-document or front-anchored (readers care about the beginning); `tail` = append-temporal stream (readers care about the latest content). Channels not listed default to `head`. Renderers use this to pick truncation direction; the amount to render is a core/runtime concern, not a contract field.",
            "propertyNames": { "pattern": "^[a-z][a-z0-9_-]*$" },
            "additionalProperties": { "enum": ["head", "tail"] }
        },
        "writable_by": {
            "type": "array",
            "items": { "enum": ["model", "client", "system", "plugin"] },
            "uniqueItems": true
        },
        "volatile": { "type": "boolean" },
        "handler": { "type": ["string", "null"] }
    }
}