/**
 * Shared string-distance helpers for "did you mean?" suggestions.
 *
 * Extracted from toolCallRepair.ts, which had the only implementation, so
 * provider-name validation can reuse it rather than carry a second copy.
 */
/**
 * Longest string the distance primitive will compare.
 *
 * Exported so every call site can apply the same limit *before* calling
 * `levenshtein` — skipping an over-limit operand entirely, rather than
 * comparing a truncated prefix of it. Truncating silently merged any two
 * strings that happened to share their first `MAX_COMPARABLE_LENGTH`
 * characters into distance 0, which let a direct MCP tool-name lookup
 * (`resolveToolName`) resolve to the wrong tool for a long, colliding name.
 */
export declare const MAX_COMPARABLE_LENGTH = 128;
/**
 * Compute Levenshtein edit distance between two strings.
 * Uses the iterative matrix approach — O(m*n) time, O(min(m,n)) space.
 *
 * Throws rather than truncating when either input exceeds
 * `MAX_COMPARABLE_LENGTH`: silently comparing truncated prefixes produces a
 * *wrong* distance (two distinct strings sharing a long prefix collapse to
 * distance 0) instead of no distance, which is worse than refusing outright.
 * Callers that want fuzzy matching over long input must apply the length
 * check themselves and skip the comparison — see `suggestClosest` below and
 * `resolveToolName`/`rankToolNameCandidates` in toolCallRepair.ts.
 */
export declare function levenshtein(a: string, b: string): number;
/**
 * Candidates within `maxDistance` edits of `input`, closest first.
 *
 * Ties break on the candidate's own order in `candidates`, so a caller that
 * passes canonical names before aliases gets the canonical one suggested.
 * Comparison is case-insensitive; the returned strings keep their original
 * casing so they can be pasted back verbatim.
 *
 * `input` longer than `MAX_COMPARABLE_LENGTH` is rejected outright (no
 * suggestions), and any individual candidate over the same limit is skipped
 * rather than compared — never truncated. Truncating either side risks
 * exactly the false distance-0 match `levenshtein`'s guard rejects: two
 * distinct strings sharing a long-enough prefix would otherwise look
 * identical and "suggest" the wrong one.
 *
 * @param input - The string the user actually typed
 * @param candidates - Valid values, most-preferred first
 * @param options.maxDistance - Edit budget (default 3)
 * @param options.limit - Most suggestions to return (default 3)
 */
export declare function suggestClosest(input: string, candidates: readonly string[], options?: {
    maxDistance?: number;
    limit?: number;
}): string[];