Rigid pipelines limit Siri, Alexa architectures

The "Slots and Intents" model was a software engineering solution to a linguistic problem, leading to extreme brittleness.

• –Pre-LLM systems were essentially massive classification trees; if you didn't hit a pre-defined intent, the system failed.
• –Dialogue management was the biggest bottleneck, often requiring manually designed state machines that couldn't handle context shifts.
• –Modern LLMs replace the entire NLU/DM/NLG pipeline with a single reasoning engine, moving from "matching" to "understanding."
• –For developers, the transition means moving from writing utterance training data to writing system prompts and tool definitions.