/**
 * Rate limit reason classification and backoff calculation utilities.
 * Ported from opencode-antigravity-auth plugin for consistency.
 */
export type RateLimitReason = "QUOTA_EXHAUSTED" | "INSUFFICIENT_G1_CREDITS_BALANCE" | "RATE_LIMIT_EXCEEDED" | "CONCURRENT_LIMIT" | "MODEL_CAPACITY_EXHAUSTED" | "SERVER_ERROR" | "UNKNOWN";
/**
 * Classify a rate-limit error message into a reason category.
 * Priority order: explicit details in a resource-exhausted error > QUOTA
 * (Antigravity "quota will reset") > CONCURRENT_LIMIT > MODEL_CAPACITY >
 * QUOTA (account) > RATE_LIMIT > QUOTA (generic) > SERVER_ERROR > bare resource-exhausted > UNKNOWN.
 *
 * Bare "resource exhausted" / "resource_exhausted" maps to MODEL_CAPACITY (transient, short wait).
 * Explicit details such as "quota exceeded" retain their normal classification.
 */
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.
 * HTTP 402 Payment Required is categorically an account-billing cap (xAI
 * Grok Build "usage balance exhausted", DeepSeek "Insufficient Balance",
 * OpenRouter credit exhaustion) — never a transient blip or bad credential.
 * 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 a usage-limit status (429/402) → 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}. `QUOTA_EXHAUSTED`
 *     rotates; for the categorical 402 billing cap a `CONCURRENT_LIMIT` body
 *     also rotates (the cap is concurrent-worded but the status is still an
 *     exhausted billing cap). `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 usage-limit status 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.js").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;
/**
 * Account-scoped cap phrasing delivered on a 403 (or a statusless Connect
 * trailer): "Reached overall message rate limit", "Your limit will reset in …".
 * Kept separate from {@link matchesUsageLimitText} because the bare wording is
 * ambiguous without the 403 / statusless-account context; consumed by both
 * {@link isUsageLimitOutcome} (rotation decision) and `flags.ts` (Flag.UsageLimit).
 */
export declare function isAccountScopedCapText(message: string): boolean;
/**
 * A concurrency cap on a non-billing status is shed-and-backoff, not
 * credential-rotatable. This mirrors the exclusion in {@link isUsageLimitOutcome}
 * for the 403 auth-retry entry points. A 402 remains a categorical billing cap.
 */
export declare function isConcurrencyCapExclusion(status: number | undefined, message: string | undefined): boolean;