Choosing a model
Name one, or say what you want and let the catalogue pick.
Preferences, not model names
Naming a model pins you to it, including when it is retired or something better ships. A preference says what matters and resolves against a live catalogue:
| preference | resolves to |
|---|---|
| cheapest | the least expensive model that can do the job |
| balanced | the default |
| best | capability first |
Or pin one
anthropic/claude-opus-4-5A named model is always honoured. The catalogue only governs automatic picks.
The catalogue is live
Prices and models change. opsen refreshes rather than shipping a rate card that quietly goes stale, and automatic picks are restricted to known publishers — a price filter alone will happily choose something nobody has heard of because it is cheap.
What it costs before it runs
/costs shows what the same token volume would have cost on other models. That is arithmetic on real usage rather than a benchmark, which makes it the honest version of "would a cheaper model have done".