/**
 * YAML frontmatter extraction and legacy field mapping for lessons.
 * Implements the dual-parse (fail-open) strategy from ADR-070.
 */
import { type LessonFrontmatter } from './types.js';
export interface FrontmatterParseResult {
    frontmatter: LessonFrontmatter;
    /** Content after the YAML block (or full content if no YAML) */
    body: string;
    /** Whether YAML frontmatter was detected (even if invalid) */
    hadYaml: boolean;
    /** Whether YAML was both detected AND validated successfully */
    validYaml: boolean;
}
/**
 * Extract YAML frontmatter from lesson content.
 * If YAML is present, parse and validate against the schema.
 * If missing or invalid, return defaults and the full content as body.
 */
export declare function extractFrontmatter(content: string, onWarn?: (msg: string) => void): FrontmatterParseResult;
/**
 * Build a LessonFrontmatter from legacy markdown fields.
 * Maps **Tags:**, **Pattern:**, **Engine:**, **Scope:**, **Severity:**, **Applies-to:** into the schema.
 */
export declare function buildFrontmatterFromLegacy(tags: string[], body: string): LessonFrontmatter;
//# sourceMappingURL=lesson-frontmatter.d.ts.map