import type { ErrorCode, EvaluationContext, FlagMetadata, FlagValue, ResolutionReason } from '@openfeature/core';
export interface EvaluationRequest {
    /**
     * Context information for flag evaluation
     */
    context?: EvaluationContext;
}
/**
 * The possible values resulting from a flag evaluation.
 * In OFREP, a "disabled" flag is represented by undefined value
 * https://github.com/open-feature/protocol/issues/46
 * https://github.com/open-feature/protocol/pull/49/files
 */
export type EvaluationFlagValue = FlagValue | undefined;
export interface MetadataResponse {
    /**
     * Arbitrary metadata for the flag, useful for telemetry and documentary purposes
     */
    metadata?: FlagMetadata;
}
export interface EvaluationSuccessResponse extends MetadataResponse {
    /**
     * Feature flag key
     */
    key?: string;
    /**
     * An OpenFeature reason for the evaluation
     */
    reason?: ResolutionReason;
    /**
     * Variant of the evaluated flag value
     */
    variant?: string;
    /**
     * Flag evaluation result
     */
    value?: EvaluationFlagValue;
}
export interface EvaluationFailureResponse extends MetadataResponse {
    /**
     * Feature flag key
     */
    key: string;
    /**
     * OpenFeature compatible error code. See https://openfeature.dev/specification/types#error-code
     */
    errorCode: ErrorCode;
    /**
     * An error description for logging or other needs
     */
    errorDetails?: string;
}
export declare function isEvaluationFailureResponse(response: unknown): response is EvaluationFailureResponse;
export type EvaluationResponse = EvaluationFailureResponse | EvaluationSuccessResponse;