---
title: "Update Agent"
method: PATCH
path: "/v1/agents/{agent_id}"
tags: ["Agents"]
---

# Update Agent

`PATCH /v1/agents/{agent_id}`

## Request

- Base URL: `https://api.agentline.cloud`
- URL: `https://api.agentline.cloud/v1/agents/{agent_id}`
- Auth: HTTP bearer

Update an AI voice agent's configuration.

Overwrites the fields you send; omitted fields keep their values and the
old values are not kept. Changes apply to the next inbound or outbound
call the agent handles; calls already in progress are unaffected.

Returns the full updated agent. Sending no fields, an unknown voice_id or
a transfer_number other than owner_phone returns HTTP 400.

## Path parameters

- `agent_id` string, required: Agent ID (agt_...) returned by create_agent or list_agents.

## Request body

- AgentUpdate
  - `name` string, nullable: New display name for the AI voice agent
  - `system_prompt` string, nullable: Updated default instructions for ALL future calls (does not affect calls already in progress)
  - `initial_greeting` string, nullable: Updated default greeting for ALL future calls (inbound and outbound)
  - `voice_id` string, nullable: New TTS voice preset name or voice UUID
  - `transfer_number` string, nullable: Number a live call is transferred to. Only the owner phone is allowed, so send the same E.164 number as owner_phone (current or in this request); setting owner_phone updates it automatically.
  - `voicemail_message` string, nullable: Updated voicemail message
  - `owner_phone` string, nullable: Updated owner phone in E.164. Also becomes the only live-call transfer destination.

## Response `200`

Successful Response

- unknown

## Other responses

- `422`: Validation Error

---

[API](https://skmtc.dev/agentline/apis/agentline-prepaid-phone-service-for-ai-agents.md) · [All operations](https://skmtc.dev/agentline/apis/agentline-prepaid-phone-service-for-ai-agents/llms.txt) · [OpenAPI document](https://skmtc.dev/agentline/apis/agentline-prepaid-phone-service-for-ai-agents/revisions/18c0bdbb4b30?raw)