{
    "$schema": "https://json-schema.org/draft/2020-12/schema",
    "$id": "https://a2ui.org/specification/v0_9/client_capabilities.json",
    "title": "A2UI Client Capabilities Schema",
    "description": "A schema for the a2uiClientCapabilities object, which is sent from the client to the server as part of the A2A metadata to describe the client's UI rendering capabilities.",
    "type": "object",
    "properties": {
        "v0.9": {
            "type": "object",
            "description": "The capabilities structure for version 0.9 of the A2UI protocol.",
            "properties": {
                "supportedCatalogIds": {
                    "type": "array",
                    "description": "The URI of each of the component and function catalogs that is supported by the client.",
                    "items": { "type": "string" }
                },
                "inlineCatalogs": {
                    "type": "array",
                    "description": "An array of inline catalog definitions, which can contain both components and functions. This should only be provided if the agent declares 'acceptsInlineCatalogs: true' in its capabilities.",
                    "items": { "$ref": "#/$defs/Catalog" }
                }
            },
            "required": ["supportedCatalogIds"]
        }
    },
    "required": ["v0.9"],
    "$defs": {
        "FunctionDefinition": {
            "type": "object",
            "description": "Describes a function's interface.",
            "properties": {
                "name": {
                    "type": "string",
                    "description": "The unique name of the function."
                },
                "description": {
                    "type": "string",
                    "description": "A human-readable description of what the function does and how to use it."
                },
                "parameters": {
                    "type": "object",
                    "description": "A JSON Schema describing the expected arguments (args) for this function.",
                    "$ref": "https://json-schema.org/draft/2020-12/schema"
                },
                "returnType": {
                    "type": "string",
                    "enum": ["string", "number", "boolean", "array", "object", "any", "void"],
                    "description": "The type of value this function returns."
                }
            },
            "required": ["name", "parameters", "returnType"],
            "additionalProperties": false
        },
        "Catalog": {
            "type": "object",
            "description": "A collection of component and function definitions.",
            "properties": {
                "catalogId": {
                    "type": "string",
                    "description": "Unique identifier for this catalog."
                },
                "components": {
                    "type": "object",
                    "description": "Definitions for UI components supported by this catalog.",
                    "additionalProperties": {
                        "$ref": "https://json-schema.org/draft/2020-12/schema"
                    }
                },
                "functions": {
                    "type": "array",
                    "description": "Definitions for functions supported by this catalog.",
                    "items": {
                        "$ref": "#/$defs/FunctionDefinition"
                    }
                },
                "theme": {
                    "title": "A2UI Theme",
                    "description": "A schema that defines a catalog of A2UI theme properties. Each key is a theme property name (e.g. 'primaryColor'), and each value is the JSON schema for that property.",
                    "type": "object",
                    "additionalProperties": {
                        "$ref": "https://json-schema.org/draft/2020-12/schema"
                    }
                }
            },
            "required": ["catalogId"],
            "additionalProperties": false
        }
    }
}