> ## Documentation Index
> Fetch the complete documentation index at: https://docs.featherhq.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Configurations

> Configure the listening, reasoning, speaking, and messaging behavior that each Feather agent version uses.

Configurations determine how an agent listens, reasons, and responds. In Feather, most of these settings live on the agent version so you can tune behavior without creating a new agent identity.

## Main Configuration Areas

* **LLM** for reasoning and response generation
* **STT** for speech recognition on call agents
* **TTS and voice** for spoken output
* **Language** for locale-aware behavior
* **Turn-taking settings** such as interruption and silence controls
* **Message settings** such as SMS or email token limits on text-capable versions

## Start with Defaults, Then Tune

For most teams, the best rollout pattern is:

1. Start with known-good default configs
2. Validate the prompt and tools first
3. Tune voice or model settings only after the baseline works

## Inspect Available Configurations

<CodeGroup>
  ```bash cURL theme={"system"}
  curl "https://prod.featherhq.com/api/v1/available-voices" \
    -H "X-API-Key: $FEATHER_API_KEY"
  ```

  ```bash cURL theme={"system"}
  curl "https://prod.featherhq.com/api/v1/llm-configs" \
    -H "X-API-Key: $FEATHER_API_KEY"
  ```

  ```bash cURL theme={"system"}
  curl "https://prod.featherhq.com/api/v1/stt-configs" \
    -H "X-API-Key: $FEATHER_API_KEY"
  ```

  ```bash cURL theme={"system"}
  curl "https://prod.featherhq.com/api/v1/tts-configs" \
    -H "X-API-Key: $FEATHER_API_KEY"
  ```
</CodeGroup>

## What to Tune First

### Voice Agents

Prioritize:

* Voice selection
* Silence timeouts
* Interruption sensitivity
* Maximum call duration

### Text Agents

Prioritize:

* Response length
* Temperature
* Inactivity timeout
* Sender identity for email

## Example Version Settings

```json theme={"system"}
{
  "llmConfigId": "YOUR_LLM_CONFIG_ID",
  "sttConfigId": "YOUR_STT_CONFIG_ID",
  "ttsConfigId": "YOUR_TTS_CONFIG_ID",
  "voiceId": "YOUR_VOICE_ID",
  "languageId": "en-US",
  "voiceSpeed": 1.0,
  "voiceVolume": 100,
  "initialSilenceTimeout": 30000,
  "finalSilenceTimeout": 10000,
  "minInterruptionWords": 1,
  "minInterruptionDuration": 1.0
}
```

## Configuration Advice

* Change one variable at a time when testing quality.
* Keep a stable production baseline for each major use case.
* Version changes to voice, prompt, and tools together when the customer experience depends on all three.
* Match tone and pacing to the job, not just brand preference.

## Related API Reference

<CardGroup cols={2}>
  <Card title="Voices API" icon="code" href="/api-reference/configuration/get-available-voices">
    List supported voices.
  </Card>

  <Card title="LLM Configs API" icon="code" href="/api-reference/configuration/get-llm-configs">
    Review model configuration options.
  </Card>

  <Card title="Languages API" icon="code" href="/api-reference/configuration/get-supported-languages">
    See supported language options.
  </Card>

  <Card title="Agents" icon="robot" href="/documentation/core-concepts/agents">
    Apply configurations at the version level.
  </Card>
</CardGroup>