/**
 * postgres-mcp - Query Helpers
 *
 * Shared utilities for tool handlers and resource files.
 * Eliminates duplicated limit-coercion, default-limit, and type-coercion logic.
 */
/** Default maximum rows returned when no limit is specified */
export declare const DEFAULT_QUERY_LIMIT = 100;
/**
 * Safe numeric coercion for z.preprocess() in SchemaBase definitions.
 *
 * z.coerce.number() converts "abc" → NaN, which Zod rejects at the SDK
 * boundary with a raw MCP -32602 error before the handler's try/catch.
 * This helper converts non-numeric values to undefined so the
 * .optional() chain kicks in and the handler receives undefined instead.
 *
 * Usage: `z.preprocess(coerceNumber, z.number().optional())`
 */
export declare function coerceNumber(val: unknown, _ctx?: unknown): unknown;
/**
 * Strict numeric coercion for z.preprocess() in schemas where silent defaulting is not desired.
 * Returns the original invalid value so Zod can catch it and yield a type error.
 */
export declare function coerceStrictNumber(val: unknown, _ctx?: unknown): unknown;
/**
 * Coerce a database row value to a JS number.
 * Handles BIGINT strings returned by the pg driver as strings.
 * Returns null for null/undefined inputs.
 */
export declare const toNum: (val: unknown) => number | null;
/**
 * Row-count threshold below which index recommendations are suppressed.
 * Used by resource handlers (vector, postgis) to skip index suggestions
 * on tables too small to benefit from them.
 */
export declare const SMALL_TABLE_THRESHOLD = 1000;
/**
 * Safely coerce an unknown database row value to a string.
 * Handles string, number, null/undefined, and object values.
 */
export declare function toStr(value: unknown): string;
/**
 * Coerce a raw limit parameter into a usable value.
 *
 * MCP clients may pass limits as strings, numbers, undefined, or 0.
 * This helper normalizes all cases:
 * - `undefined` → defaultLimit
 * - `NaN` / non-numeric strings → defaultLimit
 * - `0` → `null` (no limit — return all rows)
 * - Positive number → that number
 * - Negative / other → defaultLimit
 *
 * @param raw - Raw limit value from parsed Zod schema (may be any type)
 * @param defaultLimit - Fallback limit (default: DEFAULT_QUERY_LIMIT)
 * @returns The resolved limit, or `null` for unlimited
 */
export declare function coerceLimit(raw: unknown, defaultLimit?: number): number | null;
/**
 * Build a SQL LIMIT clause from a coerced limit value.
 *
 * @param limitVal - Resolved limit from coerceLimit(), or null for unlimited
 * @returns ` LIMIT N` string, or empty string for unlimited
 */
export declare function buildLimitClause(limitVal: number | null): string;
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