ACP: The Protocol That Lets AI Agents Actually Talk to Each Other

Modern AI assistants usually fail in one of two ways. They're confident but ungrounded, answering from generic model knowledge. Or they're grounded but narrow, stuck answering from a fixed document set. Real applications need both: reasoning with trusted internal knowledge and incorporating fresh external context when required.

The solution isn't to build one oversized agent. It's to build specialists that can be composed. But specialists need a way to communicate — and until recently, that meant writing custom glue code for every integration.