Function parseFrontmatter

eng/yaml-parser.mjs:23–57

* Parse frontmatter from a markdown file using vfile-matter * Works with any markdown file that has YAML frontmatter (agents, prompts, instructions) * @param {string} filePath - Path to the markdown file * @returns {object|null} Parsed frontmatter object or null on error

(filePath)

 * @returns {object|null} Parsed frontmatter object or null on error
 */
function parseFrontmatter(filePath) {
  return safeFileOperation(
    () => {
      const content = fs.readFileSync(filePath, "utf8");
      const file = new VFile({ path: filePath, value: content });

      // Parse the frontmatter using vfile-matter
      matter(file);

      // The frontmatter is now available in file.data.matter
      const frontmatter = file.data.matter;

      // Normalize string fields that can accumulate trailing newlines/spaces
      if (frontmatter) {
        if (typeof frontmatter.name === "string") {
          frontmatter.name = frontmatter.name.replace(/[\r\n]+$/g, "").trim();
        }
        if (typeof frontmatter.title === "string") {
          frontmatter.title = frontmatter.title.replace(/[\r\n]+$/g, "").trim();
        }
        if (typeof frontmatter.description === "string") {
          // Remove only trailing whitespace/newlines; preserve internal formatting
          frontmatter.description = frontmatter.description.replace(
            /[\s\r\n]+$/g,
            ""
          );
        }
      }

      return frontmatter;
    },
    filePath,
    null
  );
}

/**
 * Extract agent metadata including MCP server information