12 September 2026; Python 3.11.4
PASS | Python syntax
PASS | /start response
PASS | /help response
PASS | echo response
PASS | token loaded from environment
PASS | no embedded credential
PASS | polling entry point
BOUNDARY | Offline stubs only; no Telegram account, token, network, group chat, or concurrent-user behavior was tested.
PASS | long Unicode echo preserves text in bounded chunks
PASS | sender fallback
PASS | missing message guarded for all handlers
