Verified 2026-05-03 against a real Chrome browser: POSTs to
/KararlarGenelKurul/DataTablesList consistently return HTTP 418
with the WAF block page "Bilgi Güvenliği Politikaları Gereği
Kısıtlanmıştır", regardless of headers, cookies, CSRF token, or
form payload. The block is server-side at sayistay.gov.tr and
cannot be worked around client-side. The Temyiz Kurulu and Daire
endpoints are unaffected (29k/22k records still return normally).
Detect the 418 + WAF marker in all three search methods and raise
a clear RuntimeError explaining it is an upstream restriction,
instead of the cryptic "Client error '418 I'm a teapot'" that
hides the real situation from MCP clients.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
