import type { ClaudeMessage, ClaudeTextBlock, CodexAnthropicAffinityKey, CodexNativeRequest } from "../types/index.js";
/**
 * Thrown by `assertClaudeSystemPrefixShape` and `assertClaudeMessagesAlternate`
 * when the translated request does not have the shape breakpoint placement
 * (or Anthropic's role-alternation requirement) depends on. Never logged and
 * swallowed — a silent violation here defeats caching with no visible
 * symptom besides a slow-moving cache-hit-rate metric, or turns into an
 * undifferentiated Anthropic 400.
 */
export declare class ClaudeSystemPrefixShapeError extends Error {
}
/**
 * Enforces that `system` is exactly the stable developer-block prefix before
 * a caller marks breakpoint 1 on its last element. `translateCodexRequestToClaude`
 * is contracted to produce `system` containing only the developer-role-derived
 * blocks and nothing else — `environment_context` and any other per-turn
 * payload belong in `messages`. `system[system.length-1]` is only a safe
 * breakpoint-1 anchor while that invariant holds; trusting it silently would
 * be exactly the failure this guards against.
 */
export declare function assertClaudeSystemPrefixShape(system: ClaudeTextBlock[] | string | undefined, expectedLength: number): void;
/**
 * Throws, naming the offending index, when `messages` is not alternation-safe.
 *
 * Anthropic requires alternating `user`/`assistant` roles. A native Codex
 * request can carry two consecutive `user`-role items (an auto-injected
 * notice immediately followed by the literal user turn, or a synthetic
 * `environment_context` pair) — mapped 1:1 into `ClaudeMessage` entries that
 * would otherwise reach Anthropic as back-to-back `user` messages and get
 * rejected on every request that hits it. Merging same-role Codex items into
 * one Claude message with multiple content blocks is translation-correctness
 * work owned by `translateCodexRequestToClaude`, not this guard's job — this
 * only turns a missed merge into an attributable thrown error at the new
 * hop's boundary instead of an undifferentiated Anthropic 400.
 */
export declare function assertClaudeMessagesAlternate(messages: ReadonlyArray<ClaudeMessage>): void;
/**
 * Derives the session-affinity key a Codex-origin request supplies to the
 * Claude pipeline's existing session-affinity machinery, so consecutive
 * turns of one conversation route back to the account already holding their
 * cache. Preference order mirrors what a real Codex CLI capture carries:
 * `prompt_cache_key` (top-level, the client's own pre-computed key — already
 * exactly the signal being reconstructed) beats `client_metadata.thread_id`
 * beats `client_metadata.session_id`; a genuinely identity-free request
 * degrades to a prefix-derived key so at least concurrent turns of the same
 * agent config bucket together.
 *
 * The three-way prefix (`codex-thread:` / `codex-session:` / `codex-prefix:`)
 * keeps this namespace from colliding with a Claude-Code `metadata.user_id`-
 * derived UUID or with itself across cases.
 */
export declare function codexAnthropicAffinityKey(native: CodexNativeRequest): CodexAnthropicAffinityKey | undefined;