The date stamp is a trigger channel

A model that always knows "today" is not just helpful calendar UX. OpenCode-style agents inject the current date into context; open-weight LoRAs can be trained to treat that stamp as a fuse. When the date matches, the adapter wakes a different policy — including a shell the base model never showed in eval.

That is a time-release channel, not a vibe. Static red-team prompts miss it because the trigger is environmental: the date string the harness prints every turn. Freeze the clock in sandboxes. Diff behavior across forged dates. Treat "what day is it" context as untrusted input the same way you treat tool output fences.

Stack Gems will keep calling this class of catch by name. If your agent stack auto-stamps the calendar into the system prompt, assume someone can ship a LoRA that waits for a Sunday.