Middleware layer scopes tools per turn

Hot take: the core lesson is not “build a smarter router,” it is “stop wasting the model’s attention on irrelevant tools.”

• –The article is practical architecture advice, not a theory piece, and the failure modes are believable: long tool lists and multi-step conversations break selection quality fast.
• –The middleware-scoping approach is the strongest idea here because it reduces cognitive load without fragmenting the conversation into brittle sub-agents.
• –The three-layer prompt structure is likely the difference between a neat demo and something that holds up in production.
• –The repo demo makes this feel like a reusable pattern rather than a one-off anecdote.