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

# Single prompt agents

> A single prompt agent runs the whole call from one prompt, plus a few settings you configure in the dashboard or through the API.

<Steps>
  <Step title="Create the agent">
    On the Agents screen, click **Add Agent**, choose **Single Prompt**, and enter a name and voice.
  </Step>

  <Step title="Write the prompt and welcome message">
    Describe the persona, goal and rules. See [Writing a good prompt](/guides/writing-prompts).
  </Step>

  <Step title="Test in the simulator">
    Call the agent from the browser panel and read the live transcript.
  </Step>

  <Step title="Deploy">
    Click **Deploy** to make the current version live on your phone numbers.
  </Step>
</Steps>

## What you configure

| Setting | What it does |
| - | - |
| **Prompt** | Instructions that govern the whole call. You can reference [variables](/guides/variables) as `[var_name]`. |
| **Welcome Message** | If set, the agent says it word for word when it answers, then waits for the caller. If empty, the agent writes its own opening from the prompt, so each call may start a little differently. |
| **Voice** | The agent's voice. Some voices also let you adjust speaking speed from 0.7x to 1.3x. |
| **Agent can end call** | When on, you set an **End call transition** (when to hang up, for example "The caller asks to end the call") and an **End call announcement** (the closing line the agent says before hanging up). |
| **Knowledge bases** | Attach business information the agent can answer from. See [Knowledge base](/guides/knowledge-base). |
| **Vars provided** | Values injected before the call starts, such as a customer name passed in when you place an outbound call. Each can have a default. |
| **[Vars extracted](/guides/variables#extracted-variables)** | Details pulled from the transcript after the call ends, such as the reason for calling. Shown on the call page and sent in [webhooks](/webhooks). |
| **Email summaries** | Addresses that receive a summary after each call. |
| **Webhooks** | Up to 5 HTTPS endpoints notified when a call ends, with an optional signing secret and custom headers. |
| **Operating hours** | Your business hours, available to the prompt as the `[is_open]` variable. |
| **[Pronunciation](/pronunciation-guide)** | Override how specific words are spoken. Preview each one with the play button, no test call needed. |
| **STT** | Terms the agent should recognize reliably, such as brand, street or product names. |
| **General** | **Max call length** (10, 15 or 20 minutes; default 15) and **Block anonymous calls** (callers who hide their number hear a short message and the call ends). |

<Warning>
  Every setting edits the draft. Phone calls keep using the last deployed version until you click **Deploy**. The simulator always uses the draft.
</Warning>

## Managing through the API

Single prompt agents can be created and updated through the public API. The API covers the name, language, voice, prompt, welcome message, provided and extracted variables, and webhooks. A new agent created through the API is deployed right away. See the [API reference](/api-reference/overview) for [`agent-create`](/api-reference/agent-create) and [`agent-modify`](/api-reference/agent-modify).

<Tip>
  Need steps, branching, [SMS](/guides/sms), transfers or calls to your systems? Move to a [flow agent](/guides/flow-agents). See [Single prompt vs. flow agent](/guides/agent-types).
</Tip>


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