Model Sizing for Coding Agents: Bigger Is Not Always Better (opens in new tab)

AI coding agents need capable models, and that part is obvious by now. What is less obvious is that model capability is only half the problem. The other half is model fit. A model that works beautifully for one coding task can be wasteful for another. A frontier reasoning model may be the right choice for architecture, migration planning, or debugging a subtle production issue. The same model may be unnecessary for formatting code, generating a small helper function, renaming symbols, summari...