---
title: "Update an agent"
method: PUT
path: "/assistants/{model_id}"
tags: [""]
---

# Update an agent

`PUT /assistants/{model_id}`

Use this endpoint to update an agent's name, phone number, or other parameters. 
 Only the provided parameters will be updated, and others won't be removed or changed.

## Path parameters

- `model_id` string, required — Agent ID. You can find it on the agent’s page in your dashboard.

## Headers

- `Authorization` string, required

## Request body

- object
  - `end_call_reasons` string[] — Deprecated: use end_call_reasons_v2 instead. Custom conditions that trigger automatic call termination (simple string array format).
  - `description` string — Agent description.
  - `phone_number` string — The phone number attached to the agent.
  - `external_webhook_url` string — URL of the webhook that should receive data after the call, such as the transcript.
  - `is_recording` boolean — Whether the conversation should be recorded.
  - `max_duration` AssistantsModelIdPutRequestBodyContentApplicationJsonSchemaMaxDuration
    - `duration_seconds` integer — Maximum length of the call in seconds.
    - `is_enabled` boolean — Whether there's a limit on call length.
  - `voicemail_message` AssistantsModelIdPutRequestBodyContentApplicationJsonSchemaVoicemailMessage — Configuration for the message left when a voicemail is detected. Requires `greeting_message_mode` to be set to `human`.
    - `enabled` boolean — Whether voicemail message leaving is enabled.
    - `mode` 'exact_message' | 'prompt' — The mode used to generate the voicemail message.
    - `exact_message` string — The exact message to leave on the voicemail. Used when mode is `exact_message`.
    - `prompt` string — A prompt used to generate the voicemail message. Used when mode is `prompt`.
  - `name` string — Agent name.
  - `agent` Agent
    - `timezone` 'Africa/Accra' | 'Africa/Addis_Ababa' | 'Africa/Algiers' | 'Africa/Asmara' | 'Africa/Bamako' | 'Africa/Bangui' | 'Africa/Banjul' | 'Africa/Bissau' | 'Africa/Blantyre' | 'Africa/Brazzaville' | 'Africa/Bujumbura' | 'Africa/Cairo' | 'Africa/Casablanca' | 'Africa/Ceuta' | 'Africa/Conakry' | 'Africa/Dakar' | 'Africa/Dar_es_Salaam' | 'Africa/Djibouti' | 'Africa/Douala' | 'Africa/El_Aaiun' | 'Africa/Freetown' | 'Africa/Gaborone' | 'Africa/Harare' | 'Africa/Johannesburg' | 'Africa/Juba' | 'Africa/Kampala' | 'Africa/Khartoum' | 'Africa/Kigali' | 'Africa/Kinshasa' | 'Africa/Lagos' | 'Africa/Libreville' | 'Africa/Lome' | 'Africa/Luanda' | 'Africa/Lubumbashi' | 'Africa/Lusaka' | 'Africa/Malabo' | 'Africa/Maputo' | 'Africa/Maseru' | 'Africa/Mbabane' | 'Africa/Mogadishu' | 'Africa/Monrovia' | 'Africa/Nairobi' | 'Africa/Ndjamena' | 'Africa/Niamey' | 'Africa/Nouakchott' | 'Africa/Ouagadougou' | 'Africa/Porto-Novo' | 'Africa/Sao_Tome' | 'Africa/Tripoli' | 'Africa/Tunis' | 'Africa/Windhoek' | 'America/Adak' | 'America/Anchorage' | 'America/Anguilla' | 'America/Antigua' | 'America/Araguaina' | 'America/Argentina/Buenos_Aires' | 'America/Argentina/Catamarca' | 'America/Argentina/Cordoba' | 'America/Argentina/Jujuy' | 'America/Argentina/La_Rioja' | 'America/Argentina/Mendoza' | 'America/Argentina/Rio_Gallegos' | 'America/Argentina/Salta' | 'America/Argentina/San_Juan' | 'America/Argentina/San_Luis' | 'America/Argentina/Tucuman' | 'America/Argentina/Ushuaia' | 'America/Aruba' | 'America/Asuncion' | 'America/Atikokan' | 'America/Bahia' | 'America/Bahia_Banderas' | 'America/Barbados' | 'America/Belem' | 'America/Belize' | 'America/Blanc-Sablon' | 'America/Boa_Vista' | 'America/Bogota' | 'America/Boise' | 'America/Cambridge_Bay' | 'America/Campo_Grande' | 'America/Cancun' | 'America/Caracas' | 'America/Cayenne' | 'America/Cayman' | 'America/Chicago' | 'America/Chihuahua' | 'America/Ciudad_Juarez' | 'America/Costa_Rica' | 'America/Creston' | 'America/Cuiaba' | 'America/Curacao' | 'America/Danmarkshavn' | 'America/Dawson' | 'America/Dawson_Creek' | 'America/Denver' | 'America/Detroit' | 'America/Dominica' | 'America/Edmonton' | 'America/Eirunepe' | 'America/El_Salvador' | 'America/Fort_Nelson' | 'America/Fortaleza' | 'America/Glace_Bay' | 'America/Goose_Bay' | 'America/Grand_Turk' | 'America/Grenada' | 'America/Guadeloupe' | 'America/Guatemala' | 'America/Guayaquil' | 'America/Guyana' | 'America/Halifax' | 'America/Havana' | 'America/Hermosillo' | 'America/Indiana/Indianapolis' | 'America/Indiana/Knox' | 'America/Indiana/Marengo' | 'America/Indiana/Petersburg' | 'America/Indiana/Tell_City' | 'America/Indiana/Vevay' | 'America/Indiana/Vincennes' | 'America/Indiana/Winamac' | 'America/Inuvik' | 'America/Iqaluit' | 'America/Jamaica' | 'America/Juneau' | 'America/Kentucky/Louisville' | 'America/Kentucky/Monticello' | 'America/Kralendijk' | 'America/La_Paz' | 'America/Lima' | 'America/Los_Angeles' | 'America/Lower_Princes' | 'America/Maceio' | 'America/Managua' | 'America/Manaus' | 'America/Marigot' | 'America/Martinique' | 'America/Matamoros' | 'America/Mazatlan' | 'America/Menominee' | 'America/Merida' | 'America/Metlakatla' | 'America/Mexico_City' | 'America/Miquelon' | 'America/Moncton' | 'America/Monterrey' | 'America/Montevideo' | 'America/Montserrat' | 'America/Nassau' | 'America/New_York' | 'America/Nome' | 'America/Noronha' | 'America/North_Dakota/Beulah' | 'America/North_Dakota/Center' | 'America/North_Dakota/New_Salem' | 'America/Nuuk' | 'America/Ojinaga' | 'America/Panama' | 'America/Paramaribo' | 'America/Phoenix' | 'America/Port_of_Spain' | 'America/Port-au-Prince' | 'America/Porto_Velho' | 'America/Puerto_Rico' | 'America/Punta_Arenas' | 'America/Rankin_Inlet' | 'America/Recife' | 'America/Regina' | 'America/Resolute' | 'America/Rio_Branco' | 'America/Santarem' | 'America/Santiago' | 'America/Santo_Domingo' | 'America/Sao_Paulo' | 'America/Scoresbysund' | 'America/Sitka' | 'America/St_Barthelemy' | 'America/St_Johns' | 'America/St_Kitts' | 'America/St_Lucia' | 'America/St_Thomas' | 'America/St_Vincent' | 'America/Swift_Current' | 'America/Tegucigalpa' | 'America/Thule' | 'America/Tijuana' | 'America/Toronto' | 'America/Tortola' | 'America/Vancouver' | 'America/Whitehorse' | 'America/Winnipeg' | 'America/Yakutat' | 'Antarctica/Casey' | 'Antarctica/Davis' | 'Antarctica/DumontDUrville' | 'Antarctica/Macquarie' | 'Antarctica/Mawson' | 'Antarctica/McMurdo' | 'Antarctica/Palmer' | 'Antarctica/Rothera' | 'Antarctica/Syowa' | 'Antarctica/Troll' | 'Antarctica/Vostok' | 'Arctic/Longyearbyen' | 'Asia/Aden' | 'Asia/Almaty' | 'Asia/Amman' | 'Asia/Anadyr' | 'Asia/Aqtau' | 'Asia/Aqtobe' | 'Asia/Ashgabat' | 'Asia/Atyrau' | 'Asia/Baghdad' | 'Asia/Bahrain' | 'Asia/Baku' | 'Asia/Bangkok' | 'Asia/Barnaul' | 'Asia/Beirut' | 'Asia/Bishkek' | 'Asia/Brunei' | 'Asia/Chita' | 'Asia/Choibalsan' | 'Asia/Colombo' | 'Asia/Damascus' | 'Asia/Dhaka' | 'Asia/Dili' | 'Asia/Dubai' | 'Asia/Dushanbe' | 'Asia/Famagusta' | 'Asia/Gaza' | 'Asia/Hebron' | 'Asia/Ho_Chi_Minh' | 'Asia/Hong_Kong' | 'Asia/Hovd' | 'Asia/Irkutsk' | 'Asia/Jakarta' | 'Asia/Jayapura' | 'Asia/Jerusalem' | 'Asia/Kabul' | 'Asia/Kamchatka' | 'Asia/Karachi' | 'Asia/Kathmandu' | 'Asia/Khandyga' | 'Asia/Kolkata' | 'Asia/Krasnoyarsk' | 'Asia/Kuala_Lumpur' | 'Asia/Kuching' | 'Asia/Kuwait' | 'Asia/Macau' | 'Asia/Magadan' | 'Asia/Makassar' | 'Asia/Manila' | 'Asia/Muscat' | 'Asia/Nicosia' | 'Asia/Novokuznetsk' | 'Asia/Novosibirsk' | 'Asia/Omsk' | 'Asia/Oral' | 'Asia/Phnom_Penh' | 'Asia/Pontianak' | 'Asia/Pyongyang' | 'Asia/Qatar' | 'Asia/Qostanay' | 'Asia/Qyzylorda' | 'Asia/Riyadh' | 'Asia/Sakhalin' | 'Asia/Samarkand' | 'Asia/Seoul' | 'Asia/Shanghai' | 'Asia/Singapore' | 'Asia/Srednekolymsk' | 'Asia/Taipei' | 'Asia/Tashkent' | 'Asia/Tbilisi' | 'Asia/Tehran' | 'Asia/Thimphu' | 'Asia/Tokyo' | 'Asia/Tomsk' | 'Asia/Ulaanbaatar' | 'Asia/Urumqi' | 'Asia/Ust-Nera' | 'Asia/Vientiane' | 'Asia/Vladivostok' | 'Asia/Yakutsk' | 'Asia/Yangon' | 'Asia/Yekaterinburg' | 'Asia/Yerevan' | 'Atlantic/Azores' | 'Atlantic/Bermuda' | 'Atlantic/Canary' | 'Atlantic/Cape_Verde' | 'Atlantic/Faroe' | 'Atlantic/Madeira' | 'Atlantic/Reykjavik' | 'Atlantic/South_Georgia' | 'Atlantic/St_Helena' | 'Atlantic/Stanley' | 'Australia/Adelaide' | 'Australia/Brisbane' | 'Australia/Broken_Hill' | 'Australia/Darwin' | 'Australia/Eucla' | 'Australia/Hobart' | 'Australia/Lindeman' | 'Australia/Lord_Howe' | 'Australia/Melbourne' | 'Australia/Perth' | 'Australia/Sydney' | 'Europe/Amsterdam' | 'Europe/Andorra' | 'Europe/Astrakhan' | 'Europe/Athens' | 'Europe/Belgrade' | 'Europe/Berlin' | 'Europe/Bratislava' | 'Europe/Brussels' | 'Europe/Bucharest' | 'Europe/Budapest' | 'Europe/Busingen' | 'Europe/Chisinau' | 'Europe/Copenhagen' | 'Europe/Dublin' | 'Europe/Gibraltar' | 'Europe/Guernsey' | 'Europe/Helsinki' | 'Europe/Isle_of_Man' | 'Europe/Istanbul' | 'Europe/Jersey' | 'Europe/Kaliningrad' | 'Europe/Kirov' | 'Europe/Kyiv' | 'Europe/Lisbon' | 'Europe/Ljubljana' | 'Europe/London' | 'Europe/Luxembourg' | 'Europe/Madrid' | 'Europe/Malta' | 'Europe/Mariehamn' | 'Europe/Minsk' | 'Europe/Monaco' | 'Europe/Moscow' | 'Europe/Oslo' | 'Europe/Paris' | 'Europe/Podgorica' | 'Europe/Prague' | 'Europe/Riga' | 'Europe/Rome' | 'Europe/Samara' | 'Europe/San_Marino' | 'Europe/Sarajevo' | 'Europe/Saratov' | 'Europe/Simferopol' | 'Europe/Skopje' | 'Europe/Sofia' | 'Europe/Stockholm' | 'Europe/Tallinn' | 'Europe/Tirane' | 'Europe/Ulyanovsk' | 'Europe/Vaduz' | 'Europe/Vatican' | 'Europe/Vienna' | 'Europe/Vilnius' | 'Europe/Volgograd' | 'Europe/Warsaw' | 'Europe/Zagreb' | 'Europe/Zurich' | 'Indian/Antananarivo' | 'Indian/Chagos' | 'Indian/Christmas' | 'Indian/Cocos' | 'Indian/Comoro' | 'Indian/Kerguelen' | 'Indian/Mahe' | 'Indian/Maldives' | 'Indian/Mauritius' | 'Indian/Mayotte' | 'Indian/Reunion' | 'Pacific/Apia' | 'Pacific/Auckland' | 'Pacific/Bougainville' | 'Pacific/Chatham' | 'Pacific/Chuuk' | 'Pacific/Easter' | 'Pacific/Efate' | 'Pacific/Fakaofo' | 'Pacific/Fiji' | 'Pacific/Funafuti' | 'Pacific/Galapagos' | 'Pacific/Gambier' | 'Pacific/Guadalcanal' | 'Pacific/Guam' | 'Pacific/Honolulu' | 'Pacific/Kanton' | 'Pacific/Kiritimati' | 'Pacific/Kosrae' | 'Pacific/Kwajalein' | 'Pacific/Majuro' | 'Pacific/Marquesas' | 'Pacific/Midway' | 'Pacific/Nauru' | 'Pacific/Niue' | 'Pacific/Norfolk' | 'Pacific/Noumea' | 'Pacific/Pago_Pago' | 'Pacific/Palau' | 'Pacific/Pitcairn' | 'Pacific/Pohnpei' | 'Pacific/Port_Moresby' | 'Pacific/Rarotonga' | 'Pacific/Saipan' | 'Pacific/Tahiti' | 'Pacific/Tarawa' | 'Pacific/Tongatapu' | 'Pacific/Wake' | 'Pacific/Wallis' | 'US/Alaska' | 'US/Central' | 'US/Eastern' | 'US/Hawaii' | 'US/Mountain' | 'US/Pacific' — The agent's timezone.
    - `voice_prompt` string — Slightly alters the agent's intonation, talking speed or sentiment for a subtle yet noticeable effect.
    - `voice_stability` integer — Range is 0 to 1. Lower settings may make the voice sound more expressive but less predictable, while higher settings make it sound steadier but less emotional.
    - `voice_similarity_boost` integer — Range 0 to 1. Determines how closely the AI matches the original voice. Higher settings potentially including unwanted noise from the original recording.
    - `voice_optimise_streaming_latency` integer — Range 0 to 4. Optimises streaming latency
    - `voice_style` integer — Range 0 to 1. Enhances the distinct characteristics of the original voice, but may slow down processing and make the voice less stable.
    - `voice_use_speaker_boost` boolean — Amplifies the voice’s likeness to the original speaker, which can slightly slow down the response time.
    - `allowed_idle_time_seconds` integer — The agent will disconnect after this period.
    - `initial_pause_seconds` integer — Duration before the agent starts speaking.
    - `transcriber_keywords` string[] — Add business terms to improve accuracy and recognition.
    - `ring_pause_seconds` integer — Ring time before the agent answers the call.
    - `transcriber_provider` 'deepgram' | 'deepgram-nova-3' | 'synthflow-stt' — Speech-to-text provider used for transcription.
    - `transcriber_speech_recognition` 'faster' | 'high_accuracy' — Speech recognition mode for transcription speed vs quality.
    - `background_noise` AgentBackgroundNoise — Add background noise to make the call more natural.
      - `enabled` boolean — If enabled, the agent will add background noise.
      - `type` 'cafe' | 'office' — What kind of background noise should be present.
      - `volume` integer — How loud the background noise should be.
    - `noise_cancellation` 'standard' | 'advanced' — Removes background noise on the customer's side (like chatter in a café or keyboard clicks) to make their voice clearer and easier for the agent to understand.
    - `realistic_filler_words` boolean — If enabled, the agent will be using realistic filler words (for example, "um").
    - `is_transcript_disabled` boolean — If set to true, conversations will not be transcribed.
    - `redact_pii` boolean — Whether to redact personally identifiable information (PII) from transcripts, post-call webhooks, and internal logs. Redacted data includes credit card numbers, CVVs, expiration dates, social security numbers, names, email addresses, phone numbers, and physical addresses.
    - `synthesizer_filter_words` unknown[] — Words or characters that the agent should not say.
      - unknown
    - `end_call_reasons` string[] — Deprecated: use end_call_reasons_v2 instead. Custom conditions that trigger automatic call termination (simple string array format). Works with both simple prompt and Flow Designer agents.
    - `end_call_reasons_v2` AgentEndCallReasonsV2Items[] — Custom conditions that trigger automatic call termination with per-reason closing message control. When both end_call_reasons and end_call_reasons_v2 are present, v2 takes precedence.
      - `reason` string, required — The condition that triggers call termination.
      - `closing_message_mode` 'static' | 'prompt' | 'none' — Controls how the farewell message is generated. static: message is spoken verbatim. prompt: message is an instruction to the LLM. none: LLM generates its own farewell.
      - `closing_message` string — The closing message content. Interpretation depends on closing_message_mode.
    - `voice_synthesizer` 'eleven_multilingual_v2' | 'eleven_turbo_v2' | 'eleven_turbo_v2_5' | 'eleven_flash_v2' | 'eleven_flash_v2_5' | 'eleven_v3' — The engine used to synthesize voice.
    - `global_audio_tags` string — Free-form audio tags that apply to every utterance for the duration of a call. Tags are wrapped in square brackets and set a persistent voice character such as an accent or base mood. Only supported when voice_synthesizer is eleven_v3.
    - `suppression_level` number, double — Setting this value will enable voice isolation in addition to background noise detection, the value assigned the term is the strength with a higher value stronger voice isolation.
    - `interruption_fade_out` integer — Each frame is 20 ms. When you interrupt the bot, the volume slowly goes down to 0 over that many frames. For example, 5 translates to a 100 ms fadeout.
    - `voice_speed` number, double — Adjust how fast or slow your agent will talk on the call.
    - `voice_volume` number, double — Adjust how loud or quite your agent will talk on the call.
    - `min_words_to_interrupt` '0' | '1' | '2' | '3' | '4' | '5' — You can set how many words the human must speak before the AI will stop speaking and listening.
    - `prompt` string — Add variables in curly brackets. For example, <code>{your-variable}</code>.
    - `greeting_message` string — The greeting message the agent will open the conversation with. You can add variables in curly brackets (for example, <code>{your-variable}</code>).
    - `greeting_message_mode` 'human' | 'agent_static' | 'agent_dynamic' — Controls how the agent delivers the initial greeting. `human`: the agent waits for the human to speak first. `agent_static`: the agent speaks `greeting_message` once the call is established. `agent_dynamic`: the agent generates a greeting from the prompt and speaks it once the call is established. Note: `voicemail_message` requires this to be set to `human`. Changing away from `human` while `voicemail_message` is enabled will fail.
    - `greeting_message_human_talk_timeout` integer — The maximum number of seconds the agent waits for the human to speak first when `greeting_message_mode` is set to `human`. If the human does not speak within this time, the agent will start the conversation automatically.
    - `llm` 'gpt-4.1' | 'gpt-4.1-nano' | 'gpt-4.1-mini' | 'gpt-5-mini' | 'gpt-5-nano' | 'gpt-5.1' | 'gpt-5.2' | 'gpt-5.4' | 'gpt-5.4-mini' | 'gpt-5.4-nano' | 'synthflow' — The LLM powering this agent.
    - `language` 'multi' | 'en-US' | 'bg' | 'cs' | 'de-DE' | 'el' | 'fi' | 'fr-FR' | 'es-ES' | 'hu' | 'it' | 'fr' | 'pt-BR' | 'nl-NL' | 'hi' | 'zh-CN' | 'no' | 'sv-SE' | 'da' | 'da-DK' | 'id' | 'ja' | 'ko' | 'ms' | 'ro' | 'ru' | 'sk' | 'tr' | 'uk' | 'vi' | 'th' | 'pl' — This agent's language. For the list of available languages, see <a href="/about-supported-languages">Supported languages</a>
    - `voice_id` string — Voice ID for this agent. To retrieve voice IDs, use the Get voices endpoint.
    - `patience_level` 'low' | 'medium' | 'high' — Patience level of the agent.
    - `send_user_idle_reminders` boolean — Enables or disables idle reminders.
    - `reminder_after_idle_time_seconds` integer — Time in seconds before sending an idle reminder.
    - `reminder_after_idle_message` string — The idle reminder message.
    - `fallback_voice_id` string — Voice ID for this agent. To retrieve voice IDs, use the Get voices endpoint.
    - `fallback_provider` 'elevenlabs' | 'deepgram' | 'synthflow' — The provider for the fallback voice (elevenlabs, deepgram, or synthflow).
    - `fallback_model` string — The model to be used by the fallback provider.

## Response `200`

200

- UpdateAssistantResponse200
  - `status` string — Whether the request was successful.
  - `response` AssistantsModelIdPutResponsesContentApplicationJsonSchemaResponse
    - `model_id` string — Agent ID. You can find it on the agent’s page in your dashboard.
  - `details` AssistantsModelIdPutResponsesContentApplicationJsonSchemaDetails
    - `phone` string — The phone number attached to the agent.
    - `voice` string — The agent's voice.

## Other responses

- `400` — 400

---

[API](https://skmtc.net/synthflow/apis/platform-api.md) · [All operations](https://skmtc.net/synthflow/apis/platform-api/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/synthflow/platform-api/versions/decb652b52e0/schema)