import type OpenAI from "openai";
/**
 * Heuristic issues detected in a `messages` array before it's sent to the
 * provider. These are defensive checks — upstream code is supposed to
 * produce valid conversations, but historical bugs (and the many providers
 * reachable via OpenRouter) have surfaced invalid shapes that different
 * providers reject in different ways. Logging and healing here keeps a
 * single run from failing outright when the shape is still salvageable.
 */
export type MessageIssueKind = "empty_messages" | "trailing_assistant_with_content" | "trailing_assistant_empty" | "orphan_tool_result" | "dangling_tool_calls_unanswered" | "empty_assistant_mid" | "empty_user_content";
export interface MessageIssue {
    kind: MessageIssueKind;
    index: number;
    detail: string;
    healed: boolean;
}
export interface ValidateAndHealResult {
    messages: OpenAI.ChatCompletionMessageParam[];
    issues: MessageIssue[];
}
/**
 * Run sanity checks against the outgoing `messages` array and attempt to
 * heal any detected issues. Returns the (possibly modified) messages along
 * with a list of issues found — the caller should log these as errors.
 *
 * Heuristics:
 *  - Empty array → flagged, not healable (provider will reject).
 *  - Trailing assistant with content → append a synthetic user turn so
 *    providers that don't support assistant prefill (Azure-hosted Claude
 *    via OpenRouter) accept the request.
 *  - Trailing assistant with no content / no tool_calls → drop it, then
 *    re-check the new tail.
 *  - Assistant with `tool_calls` not followed by matching tool results →
 *    strip the unanswered tool_calls. If the message has no other content
 *    either, drop it. Without this, the provider rejects the next turn.
 *  - Tool message whose `tool_call_id` doesn't match any preceding
 *    assistant `tool_calls` → drop the orphan.
 *  - Mid-conversation assistant with no content and no tool_calls → drop.
 *  - User message with entirely empty content → drop.
 */
export declare function validateAndHealMessages(input: OpenAI.ChatCompletionMessageParam[], 
/**
 * Tool-call ids that are
 * *legitimately* open — a suspended `ask` awaiting a human answer. This is the
 * UNIVERSAL strip site (the host runs it before every model call),
 * and the never-send-unpaired invariant means a correct array never carries a
 * suspended call here unpaired. So this set is a **fail-loud assertion**, NOT a
 * silent-keep: if an allowed id reaches the validator unpaired, resume failed to
 * thread its answer — surface the bug rather than strip it (which would mask it)
 * or send it (which the provider would 400 on). Bounded to ids in the set:
 * callers that pass nothing (every legacy/non-HITL path) get exactly today's
 * non-throwing heal-and-log behaviour.
 */
allowedOpenToolCallIds?: ReadonlySet<string>): ValidateAndHealResult;