> For the full page index, fetch https://echonova.ai/llms.txt

# Choose a model and reasoning effort

Pick the model that answers for an agent, set how hard it reasons before it replies, and understand the latency and cost that comes with each choice.

Every agent runs on one model, and on models that support it you can also set how
hard that model reasons before it answers. Both live on the **Voice** tab, under
**Model**, described as **The provider and model that power replies.**

## What you need

- An agent that is not archived. The **Change** button is disabled on an
  archived agent.
- Nothing else. The model list is offered to every workspace member who can open
  the agent.

## Steps

### Step 1: Open the Model section

Open the agent and select the **Voice** tab. Scroll past **Used Voices** to
**Model**. The card shows the provider name above the model id, for example
`OpenAI` above `gpt-5.4`.

### Step 2: Open the picker

Press **Change**. A sheet titled **Model** opens with the current model and, on
models that accept it, the reasoning control. Press the model row to open
**Choose a model**.

### Step 3: Pick a model

The list is grouped by provider, groups sorted alphabetically. A model still in
preview carries a **Preview** chip. Press one to select it and the picker closes
on the new choice. Nothing is saved yet.

Under each model's name the picker shows **≈** N **credits / min on your
plan**: an estimate of a voice-call minute on that model, 2,500 credits for
the call plus about 16,000 AI tokens, at the rate of your plan's credits.
Hover the line for the provider's price per 1M tokens, the 10% fee, and the
same prices in credits on your plan.

You never choose the provider. It follows the model you pick, which is what the
hint under the list means: **The model this agent runs on. The provider is set
automatically.**

### Step 4: Set the reasoning effort

The **Reasoning effort** control appears only when the selected model supports
it. Its five segments are **Default**, **Minimal**, **Low**, **Medium** and
**High**, and the portal describes them as **How hard the model reasons before
it answers. Higher effort can improve quality but adds latency.**

**Default** sends no reasoning setting at all, so the model does whatever it does
on its own.

### Step 5: Close the sheet

Press **Done**. Closing the sheet saves the agent.

## Get it right

Reasoning happens before the first word, so on a voice call it is heard as
silence while the caller waits. Match the effort to how the caller experiences a
pause.

**Recommended**

- Voice calls: **Default** or **Minimal**, and let the prompt do the work of
  keeping answers short.
- Helpdesk tickets and email-shaped replies: **Medium** or **High**, where a
  second of thinking costs the reader nothing.

**Less effective**

- **High** on a live phone agent, which buys a better sentence at the price of a
  silence the caller hears as a dropped call.
- Raising the effort to fix an answer that is wrong because the prompt is vague
  or the document is missing.

## Worked example

A support agent on the phone is answering well but slowly. You open **Model**,
leave the model as it is and move **Reasoning effort** from **High** to
**Minimal**, then press **Done**.

The next call starts on the new setting; the one in progress does not change.
Compare the model's time on a few turns in
[Conversations](/docs/agents/conversations) before and after, and check the
credits on those turns: less reasoning means fewer tokens, so the model's share
of each turn falls with the latency.

## What happens next

The next conversation starts on the new model and effort. A call already running
finishes on the model it started with.

## Which models you can pick

The picker is not a fixed list. It shows the chat models available to your
workspace, so it changes as they change:

- A model that is retired stops appearing. If an agent is still set to it, calls
  use the default model, and the page shows a red note naming it until you pick
  another model.
- A newly available model can take up to 5 minutes to appear in the picker, and
  up to 24 hours before its reasoning support is recognised.

## Which models accept reasoning effort

The **Reasoning effort** control appears only on models that accept it, which
today are the `o1`, `o3`, `o4` and `gpt-5` families.

The same rule is applied when you save. Move an agent to a model that does not
accept the setting and the effort is cleared and stored empty, so a stale effort
is never sent to a model that would reject it.

## What reasoning effort changes

Reasoning effort is passed to the model unchanged, so the exact behaviour is the
model's own. The trade it makes is always the same shape.

| Setting     | What to expect                                 | Where it fits                                                      |
| ----------- | ---------------------------------------------- | ------------------------------------------------------------------ |
| **Default** | Whatever the model does unprompted             | Start here and change it only if you have a reason                 |
| **Minimal** | The least deliberation, the fastest first word | Voice calls where a pause is worse than a slightly worse answer    |
| **Low**     | A small amount of deliberation                 | Short factual exchanges                                            |
| **Medium**  | Noticeably more deliberation                   | Text channels where the customer is reading, not waiting on a line |
| **High**    | The most deliberation, the longest wait        | Tickets and email-shaped work, rarely live voice                   |

Two costs move together with the setting.

**Latency.** Reasoning happens before the first token, so on a voice call it
lands as silence between the caller finishing and the agent starting. The model's
time is recorded on every turn, so you can compare settings against real
conversations rather than guessing.

**Credits.** Every turn reports its prompt and completion tokens, and the turn's AI usage is priced from them at the provider's price plus 10%. More reasoning means more
tokens, so a higher effort costs more per turn on the same conversation.

## Temperature

Every agent runs at temperature `0.7`. Changing it is not available from the portal
today.

## Limits

| Limit                                       | Value                                       | Applies to                       |
| ------------------------------------------- | ------------------------------------------- | -------------------------------- |
| Reasoning effort values                     | Empty, `minimal`, `low`, `medium` or `high` | The **Reasoning effort** control |
| Reasoning effort on an unsupported model    | Cleared on save                             | The **Reasoning effort** control |
| Temperature                                 | `0.7`                                       | Every agent                      |
| Models offered                              | The chat models available to your workspace | The picker                       |
| A new model appearing in the picker         | Up to 5 minutes                             | The picker                       |
| Reasoning support recognised on a new model | Up to 24 hours                              | The **Reasoning effort** control |
| When a saved change applies                 | The next conversation                       | The agent                        |

## Troubleshooting

### This model is no longer available. Pick another to keep this agent working.

The model saved on this agent is not in the current list. The agent keeps
starting conversations on it, and nothing guarantees it will answer. Pick a
current model. Until you do, you can still save changes to the agent's other
settings.

### Couldn't load the model list. Showing your current selection.

The list could not be fetched. The picker falls back to a single row holding the
agent's current model, so you can close the sheet without changing anything.
Reopen it later.

### The reasoning control is not in the sheet

The selected model does not accept a reasoning setting, or the list failed to
load and the fallback row reports none. Pick a supported model and the control
appears.

## FAQ

### What does Default actually do?

It sends no reasoning setting, and the model behaves as it does without one.

### Does a higher effort cost more?

Yes. Reasoning produces tokens, tokens are reported on the turn, and the model's
share of the turn's credits is priced from them.

### Can I set a different model per channel?

No. The model belongs to the agent, and every channel it serves uses it.

### Can I change the temperature?

Not from the portal today. Every agent runs at `0.7`.

### Does changing the model interrupt a call in progress?

No. The change applies at the start of the next conversation.

### Which provider will my agent use?

The one that offers the model you picked. The picker groups models by provider,
and the provider is always the one the chosen model belongs to.

## Related

- [How the prompt is assembled](/docs/agents/prompting-guide): what the model reads
- [Voices and language](/docs/agents/voice-and-language): the voice that speaks its answers
- [What a turn costs](/docs/agents/what-a-turn-costs): how the model's share is priced
- [Write the persona](/docs/agents/persona): the wording that beats a bigger model
- [What is an agent](/docs/agents/what-is-an-agent): the rest of an agent's settings