Interface SessionState<S>

interface SessionState<S = unknown> {
    artifacts?: {
        metadata?: Record<string, any>;
        name?: string;
        parts: (
            | {
                custom?: Record<string, unknown>;
                data?: unknown;
                media?: undefined;
                metadata?: Record<string, unknown>;
                reasoning?: undefined;
                resource?: undefined;
                text: string;
                toolRequest?: undefined;
                toolResponse?: undefined;
            }
            | {
                custom?: Record<string, unknown>;
                data?: unknown;
                media: { contentType?: string; url: string };
                metadata?: Record<string, unknown>;
                reasoning?: undefined;
                resource?: undefined;
                text?: undefined;
                toolRequest?: undefined;
                toolResponse?: undefined;
            }
            | {
                custom?: Record<string, unknown>;
                data?: unknown;
                media?: undefined;
                metadata?: Record<string, unknown>;
                reasoning?: undefined;
                resource?: undefined;
                text?: undefined;
                toolRequest: {
                    input?: unknown;
                    name: string;
                    partial?: boolean;
                    ref?: string;
                };
                toolResponse?: undefined;
            }
            | {
                custom?: Record<string, unknown>;
                data?: unknown;
                media?: undefined;
                metadata?: Record<string, unknown>;
                reasoning?: undefined;
                resource?: undefined;
                text?: undefined;
                toolRequest?: undefined;
                toolResponse: { name: string; output?: unknown; ref?: string } & {
                    content?: (
                        (...)
                        | (...)
                        | (...)
                        | (...)
                        | (...)
                        | (...)
                        | (...)
                        | (...)
                    )[];
                };
            }
            | {
                custom?: Record<string, unknown>;
                data?: unknown;
                media?: undefined;
                metadata?: Record<string, unknown>;
                reasoning?: undefined;
                resource?: undefined;
                text?: undefined;
                toolRequest?: undefined;
                toolResponse?: undefined;
            }
            | {
                custom: Record<string, any>;
                data?: unknown;
                media?: undefined;
                metadata?: Record<string, unknown>;
                reasoning?: undefined;
                resource?: undefined;
                text?: undefined;
                toolRequest?: undefined;
                toolResponse?: undefined;
            }
            | {
                custom?: Record<string, unknown>;
                data?: unknown;
                media?: undefined;
                metadata?: Record<string, unknown>;
                reasoning: string;
                resource?: undefined;
                text?: undefined;
                toolRequest?: undefined;
                toolResponse?: undefined;
            }
            | {
                custom?: Record<string, unknown>;
                data?: unknown;
                media?: undefined;
                metadata?: Record<string, unknown>;
                reasoning?: undefined;
                resource: { uri: string };
                text?: undefined;
                toolRequest?: undefined;
                toolResponse?: undefined;
            }
        )[];
    }[];
    custom?: S;
    messages?: {
        content: (
            | {
                custom?: Record<string, unknown>;
                data?: unknown;
                media?: undefined;
                metadata?: Record<string, unknown>;
                reasoning?: undefined;
                resource?: undefined;
                text: string;
                toolRequest?: undefined;
                toolResponse?: undefined;
            }
            | {
                custom?: Record<string, unknown>;
                data?: unknown;
                media: { contentType?: string; url: string };
                metadata?: Record<string, unknown>;
                reasoning?: undefined;
                resource?: undefined;
                text?: undefined;
                toolRequest?: undefined;
                toolResponse?: undefined;
            }
            | {
                custom?: Record<string, unknown>;
                data?: unknown;
                media?: undefined;
                metadata?: Record<string, unknown>;
                reasoning?: undefined;
                resource?: undefined;
                text?: undefined;
                toolRequest: {
                    input?: unknown;
                    name: string;
                    partial?: boolean;
                    ref?: string;
                };
                toolResponse?: undefined;
            }
            | {
                custom?: Record<string, unknown>;
                data?: unknown;
                media?: undefined;
                metadata?: Record<string, unknown>;
                reasoning?: undefined;
                resource?: undefined;
                text?: undefined;
                toolRequest?: undefined;
                toolResponse: { name: string; output?: unknown; ref?: string } & {
                    content?: (
                        (...)
                        | (...)
                        | (...)
                        | (...)
                        | (...)
                        | (...)
                        | (...)
                        | (...)
                    )[];
                };
            }
            | {
                custom?: Record<string, unknown>;
                data?: unknown;
                media?: undefined;
                metadata?: Record<string, unknown>;
                reasoning?: undefined;
                resource?: undefined;
                text?: undefined;
                toolRequest?: undefined;
                toolResponse?: undefined;
            }
            | {
                custom: Record<string, any>;
                data?: unknown;
                media?: undefined;
                metadata?: Record<string, unknown>;
                reasoning?: undefined;
                resource?: undefined;
                text?: undefined;
                toolRequest?: undefined;
                toolResponse?: undefined;
            }
            | {
                custom?: Record<string, unknown>;
                data?: unknown;
                media?: undefined;
                metadata?: Record<string, unknown>;
                reasoning: string;
                resource?: undefined;
                text?: undefined;
                toolRequest?: undefined;
                toolResponse?: undefined;
            }
            | {
                custom?: Record<string, unknown>;
                data?: unknown;
                media?: undefined;
                metadata?: Record<string, unknown>;
                reasoning?: undefined;
                resource: { uri: string };
                text?: undefined;
                toolRequest?: undefined;
                toolResponse?: undefined;
            }
        )[];
        metadata?: Record<string, unknown>;
        role: "user" | "model" | "tool" | "system";
    }[];
    sessionId?: string;
}