Why model routing matters more than model loyalty in AI engineering

The core rule for professional AI-assisted engineering is 'route by task, not by habit.' Not every task needs a frontier model like Opus or GPT-5. Fine-tuned, task-specific models — like Cognition's SWE 1.7, built specifically for coding — are dramatically cheaper and often sufficient for the repetitive reinforcement loops that make up the bulk of agentic work. A session running on SWE 1.7 might cost around five dollars, whereas blindly routing everything through a top-tier frontier model inflates costs with no proportional gain. The expert's position is simple: if you haven't learned to use the right model for the right task, you're wasting money and setting yourself up for a cost ceiling that will eventually kill your engineering motion.