Function loadSkillFromFile

sdk/src/skills/load-skills.ts:46–104

* Loads a single skill from a SKILL.md file. * Returns null if the skill is invalid.

(
  skillDir: string,
  skillFilePath: string,
  verbose: boolean,
)

 * Returns null if the skill is invalid.
 */
function loadSkillFromFile(
  skillDir: string,
  skillFilePath: string,
  verbose: boolean,
): SkillDefinition | null {
  const dirName = path.basename(skillDir)

  // Read the file
  let content: string
  try {
    content = fs.readFileSync(skillFilePath, 'utf8')
  } catch {
    if (verbose) {
      console.error(`Failed to read skill file: ${skillFilePath}`)
    }
    return null
  }

  // Parse frontmatter
  const parsed = parseFrontmatter(content)
  if (!parsed) {
    if (verbose) {
      console.error(`Invalid frontmatter in skill file: ${skillFilePath}`)
    }
    return null
  }

  // Validate frontmatter
  const result = SkillFrontmatterSchema.safeParse(parsed.frontmatter)
  if (!result.success) {
    if (verbose) {
      console.error(
        `Invalid skill frontmatter in ${skillFilePath}: ${result.error.message}`,
      )
    }
    return null
  }

  const frontmatter = result.data

  // Verify name matches directory name
  if (frontmatter.name !== dirName) {
    if (verbose) {
      console.error(
        `Skill name '${frontmatter.name}' does not match directory name '${dirName}' in ${skillFilePath}`,
      )
    }
    return null
  }

  return {
    name: frontmatter.name,
    description: frontmatter.description,
    license: frontmatter.license,
    metadata: frontmatter.metadata,
    content,
    filePath: skillFilePath,
  }