Function detectEngineTier

lib/gstack-memory-helpers.ts:222–249

()

 * tracing.
 */
export function detectEngineTier(): EngineDetect {
  // Try cache first
  if (existsSync(engineCachePath())) {
    try {
      const stat = statSync(engineCachePath());
      const ageMs = Date.now() - stat.mtimeMs;
      if (ageMs < ENGINE_CACHE_TTL_MS) {
        const cached = JSON.parse(readFileSync(engineCachePath(), "utf-8")) as EngineDetect;
        if (cached.schema_version === 1) return cached;
      }
    } catch {
      // Cache corrupt; fall through to fresh detect.
    }
  }

  const fresh = freshDetectEngineTier();
  try {
    mkdirSync(dirname(engineCachePath()), { recursive: true });
    writeFileSync(
      engineCachePath(),
      JSON.stringify({ ...fresh, last_writer: "gstack-memory-helpers.detectEngineTier" }, null, 2),
      "utf-8"
    );
  } catch {
    // Cache write failure is non-fatal.
  }
  return fresh;
}

// Returns gbrain's config.json path, honoring GBRAIN_HOME env var with a
// fallback to ~/.gbrain. gbrain >=0.25 dropped the top-level `engine` field