Every Models & LLM APIs comparison and buyer's guide for building AI agents — 6 pieces and counting. Each is a head-to-head or a “best X for Y” roundup with a sources-backed verdict.
OpenAI now ships three ways to call its models — but one of them has a death date. Here is how to choose, and the one reason reasoning models behave better on the newest surface.
Agents don't run on chatbot leaderboards. The model that wins your tool loop is decided by function-calling reliability, agentic benchmarks, and an "agent tax" the headline price hides.
A frontier model on every node is the default, not the optimum. Most agent calls are narrow, repetitive, and format-constrained — exactly the shape a small model was built for.
The benchmark you compare on today expires in three weeks. The license you build on doesn't. Pick an open-weight family the way it will still matter next quarter — by what you're allowed to do with it, and what it costs to serve.
An MoE model computes like a small model and remembers like a giant one. That split is great for a token factory and a trap for a single self-hosted agent.
The open-versus-closed debate in agents is framed as a fight over frameworks — but the real leverage moved to a layer where the distinction barely applies.