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The model panel picks the brain that writes the replies, the backup brain, and how much work the agent may do before it has to answer.

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Primary Model

The model every reply goes through. Available models fall into two kinds, and the panel changes depending on which you pick.
Start on callkaro/arjuna-2.5. It is CallKaro’s own model and the default for new chat agents. Move to a larger model only when you have a concrete failure it does not handle.

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Temperature

0 to 2, default 0.5. Low is precise and repeatable; high is more varied. For support and sales agents that must stay on-message, stay at or below 0.7.

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Reasoning Effort

low / medium / high (and xhigh on gpt-5.2-chat), default medium. Higher effort handles more complex logic but is slower and costs more — and on a chat channel, slower is visible to the customer as a longer wait.

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Secondary Model

A required backup, defaulting to gpt-5.4-nano.
The secondary is used only when the primary errors — a timeout, a 5xx, or a rate limit. It is not a quality fallback: a primary that replies badly is still the reply the customer gets.
Pick a secondary from a different provider than the primary. A backup on the same provider does nothing during a provider-wide outage, which is the case it exists for.

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Max Function Rounds

0 to 6, default 3. How many rounds the agent may spend calling functions before it must reply. The reply itself is always one additional round. Each round is another model call, so higher values mean slower replies and higher cost. Raise it only if you can see the agent running out of rounds mid-task.

Conversation & Features

History, limits and channel features

Functions

What those rounds are spent on