Choosing a model

Every agent runs on a model from the connect0 model catalog. The catalog is the single source of truth for which models are available, what modality they serve (chat, embedding, and so on), and what they cost. This page is a reference for choosing one.

The model catalog

Each catalog entry has a slug like openai/text-embedding-3-small, a provider, a modality, and pricing. The runtime resolves a model by its slug at call time and applies your account's allow/deny rules before the call goes out. A model that's retired or not allowed on your account is rejected at resolve time rather than failing mid-run.

Pinning a model to an agent

Set the agent's runtime model to a catalog slug. If you pin nothing, the agent has no model to think with and its runs stop early (see Why did my run fail?). Pin explicitly so the agent's behavior is predictable and you know what each run costs.

Governing which models are allowed

At the account level you can constrain the catalog:

• An allowlist restricts agents to a named set of models — anything not listed is rejected.
• A denylist blocks specific models even when no allowlist is set.

Use these to keep expensive or unapproved models out of agent runs entirely.

Balancing capability and cost

Model usage is normally the largest driver of credit spend — see Credits and pricing. Pick the smallest model that does the job: reserve the most capable models for agents that need deep reasoning, and use cost-optimized models for high-volume, simple tasks. If you have a direct provider contract, you can also bring your own key so those tokens bill against it.

Where to go next

• The model catalog for the full reference of available models and their capabilities.
• Model dispatch for how the slug you pin becomes the model actually called at runtime.