Two invariants only a live homeserver can check, now enforced rather than verified by hand: - The configured NISSE_MATRIX_USER_ID must be the token's real owner. MatrixTransport filters its own messages by comparing sender to that value, so a mismatch would make the bot read its own posts as operator input. - The account must be a testing identity, so a stray live run can never act as the production agent. Both hold today; this keeps them holding when the production nisse-dev account is created. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>