/**
 * Tool Use/Result Pair Repair
 *
 * After compaction (or a pointer-based history slice) the message array can
 * contain a `tool_call` whose `tool_result` was dropped, or a `tool_result`
 * whose `tool_call` was dropped. Providers reject both, so orphans are filled
 * with synthetic placeholders.
 *
 * Pairing is BATCH- and ID-aware, not adjacency-based. A single agent step
 * with parallel tool calls is persisted as every `tool_call` followed by every
 * `tool_result` (see flushPendingToolData), so `tool_call` is routinely
 * followed by another `tool_call` in perfectly healthy history. Matching on
 * adjacency treats that as an orphan and injects a bogus "result unavailable"
 * over a result that is present a few entries later.
 *
 * Two modes, chosen per batch:
 *   - ID mode      — `toolCallId` present: pair by id, order-independent.
 *   - legacy mode  — sessions written before `toolCallId` existed: pair
 *                    positionally WITHIN the batch (call[i] ↔ result[i]).
 */
import type { ChatMessage, RepairResult } from "../types/index.js";
/**
 * Move a summarize/keep split so it never falls INSIDE a tool batch.
 *
 * `splitIndex` means "messages[0..splitIndex) get summarized" — so the summary
 * pointer lands on messages[splitIndex - 1]. Landing mid-batch leaves the
 * recent window starting on an orphaned `tool_result`, which providers reject.
 *
 * Preferred direction is BACKWARD (summarize less, keep the whole batch in the
 * recent window) since that never loses detail. When the batch starts at index
 * 0 there is nothing left to summarize, so the split moves forward past the
 * batch instead — the caller's "at least one message summarized" invariant
 * wins over keeping the batch recent.
 */
export declare function snapSplitToBatchBoundary(messages: ChatMessage[], splitIndex: number): number;
/**
 * Repair orphaned tool_call/tool_result pairs in a message array.
 *
 * Guarantees on return: every `tool_call` is followed (within its batch) by
 * exactly one `tool_result`, and no `tool_result` precedes its `tool_call`.
 * A healthy batch — including a parallel one — is returned untouched.
 */
export declare function repairToolPairs(messages: ChatMessage[]): RepairResult;