export type AgentSqlDialect = "postgres" | "bigquery";
export type AgentSqlTokenKind = 
/** Unquoted keyword or identifier. `value` is case-folded. */
"word"
/** `"name"` on Postgres, `` `name` `` on BigQuery. `value` is the exact name. */
 | "quoted-identifier" | "string" | "number"
/** `?`, `$1`, or BigQuery `@name` / `@@name`. */
 | "parameter" | "operator" | "punctuation";
export interface AgentSqlToken {
    kind: AgentSqlTokenKind;
    /** Source text of the token. */
    text: string;
    /** Identifier name as the database resolves it; source text otherwise. */
    value: string;
    start: number;
    end: number;
}
export type AgentSqlSyntaxErrorCode = "unterminated" | "unsupported_syntax" | "unexpected_character";
/**
 * The lexer could not read the SQL the way the database would. Callers must
 * refuse to run the statement: a guard that skipped what it could not read
 * would be checking different text from what executes.
 */
export declare class AgentSqlSyntaxError extends Error {
    readonly code: AgentSqlSyntaxErrorCode;
    readonly position: number;
    constructor(code: AgentSqlSyntaxErrorCode, message: string, position: number);
}
/**
 * Splits agent-authored SQL into the tokens the target database will see.
 * Comments and whitespace are dropped; everything else is kept with its
 * source offsets. Throws {@link AgentSqlSyntaxError} for anything the lexer
 * cannot read the same way the database does.
 */
export declare function lexAgentSql(sql: string, options: {
    dialect: AgentSqlDialect;
}): AgentSqlToken[];