/**
 * Rate limit reason classification and backoff calculation utilities.
 * Ported from opencode-antigravity-auth plugin for consistency.
 */
export type RateLimitReason = "QUOTA_EXHAUSTED" | "RATE_LIMIT_EXCEEDED" | "MODEL_CAPACITY_EXHAUSTED" | "SERVER_ERROR" | "UNKNOWN";
/**
 * Classify a rate-limit error message into a reason category.
 * Priority order: QUOTA (Antigravity "quota will reset") > MODEL_CAPACITY > QUOTA (account) >
 * RATE_LIMIT > QUOTA (generic) > SERVER_ERROR > UNKNOWN.
 *
 * "resource exhausted" maps to MODEL_CAPACITY (transient, short wait)
 * "quota exceeded" / "quota will reset" maps to QUOTA_EXHAUSTED (long wait, switch account)
 */
export declare function parseRateLimitReason(errorMessage: string): RateLimitReason;
/**
 * Calculate backoff delay in ms for a given rate limit reason.
 * MODEL_CAPACITY gets jitter to prevent thundering herd.
 */
export declare function calculateRateLimitBackoffMs(reason: RateLimitReason): number;
/**
 * HTTP status codes that, absent richer body classification, represent an
 * account-local usage cap rather than a bad credential or a transient blip.
 * Always combine with {@link isUsageLimitOutcome} when a message is available
 * — a 429 carrying transient rate-limit wording is NOT a usage cap.
 */
export declare function isUsageLimitStatus(status: number | undefined): boolean;
/**
 * Returns true for failures that should burn one credential and rotate to a
 * sibling account. Decision tree:
 *
 *  1. Body matches {@link isUsageLimitError} (Codex `usage_limit_reached`,
 *     Anthropic account rate-limit, Google `resource_exhausted`, OpenAI
 *     `insufficient_quota`, …) → rotate.
 *  2. Status is not 429 → backoff (caller's domain).
 *  3. Body is absent or {@link isOpaqueStatusBody opaque} (just the status,
 *     empty JSON, HTTP framing only) → rotate conservatively: the server
 *     gave us nothing else to go on.
 *  4. Body has content → defer to {@link parseRateLimitReason}. Only
 *     `QUOTA_EXHAUSTED` rotates; `RATE_LIMIT_EXCEEDED` (`Too many requests`,
 *     per-minute caps), `MODEL_CAPACITY_EXHAUSTED` (`Service overloaded`),
 *     `SERVER_ERROR`, and `UNKNOWN` (`Please retry in 5s`) stay in the
 *     provider's own backoff layer so transient 429s don't burn sibling
 *     credentials.
 */
export declare function isUsageLimitOutcome(status: number | undefined, message: string | undefined): boolean;
/**
 * A 429 body is opaque when it carries no signal beyond the status itself —
 * empty, whitespace-only, the status digits with HTTP/JSON framing, or
 * generic punctuation. Anything else (retry hints, capacity wording, error
 * descriptions) is informative enough to defer to the classifier.
 */
export declare function isOpaqueStatusBody(message: string): boolean;
/**
 * Internal text matcher for usage/quota-limit phrasing. NOT part of the public
 * API — callers classify through {@link import("./flags").isUsageLimit} (the
 * flag accessor). `flags.ts` consumes this to populate `Flag.UsageLimit`, and
 * {@link isUsageLimitOutcome} uses it for the account-rotation decision.
 */
export declare function matchesUsageLimitText(errorMessage: string): boolean;