> ## Documentation Index > Fetch the complete documentation index at: https://heygen-1fa696a7.mintlify.site/llms.txt > Use this file to discover all available pages before exploring further. # Create Custom Agent Video > Kicks off a custom-agent run from a topic prompt. Returns a video_id immediately; poll GET /v3/custom-agents/{agent_id}/videos/{video_id} for status + rendered MP4 URL. Assets (screen recording, still, wallpaper) come from POST /v3/assets/direct-uploads — pass the resulting URL in the matching *_url field. ## OpenAPI ````yaml /openapi/external-api.json post /v3/custom-agents/{agent_id}/videos openapi: 3.1.0 info: title: HeyGen External API version: 1.0.0 description: >- HeyGen's external API for programmatic AI video creation. See https://docs.heygen.com for full documentation. contact: name: HeyGen Product Infra url: https://heygen.com servers: - url: https://api.heygen.com description: Production security: - ApiKeyAuth: [] - BearerAuth: [] tags: - name: Video Agent description: Create videos from text prompts using AI - name: Videos description: Create, list, retrieve, and delete videos - name: Templates description: Generate videos from reusable templates by replacing their variables - name: Voices description: Text-to-speech and voice management - name: Audio description: Search the background-music and sound-effects catalog - name: Video Translate description: Translate videos into other languages - name: AI Clipping description: Turn long-form videos into ready-to-share short clips with captions - name: Batches description: Create and track batches of videos. - name: Video Translation Batches description: Create and track batches of video translations. - name: Lipsync Batches description: Create and track batches of lipsyncs. - name: Asset Batches description: Create and track batches of direct-to-S3 asset uploads. - name: User description: Account information and billing - name: API Keys description: Inspect the API key authenticating the current request - name: Avatars description: List and manage avatars and looks - name: Assets description: Upload files for use in video creation - name: Webhooks description: Manage webhook endpoints and events - name: Lipsync description: Dub or replace audio on existing videos - name: Brand description: >- Brand-related resources — brand kits (colors, fonts, logos) and brand glossaries (custom term translations) - name: Custom Agents description: >- Custom agents — installed agent registry + per-agent video generation. Chiron (Apple-app tips) is the first agent. - name: HyperFrames description: Render HyperFrames composition zips into video — separate from /v3/videos - name: Filler Word Removal description: '' paths: /v3/custom-agents/{agent_id}/videos: post: tags: - Custom Agents summary: Create Custom Agent Video description: >- Kicks off a custom-agent run from a topic prompt. Returns a video_id immediately; poll GET /v3/custom-agents/{agent_id}/videos/{video_id} for status + rendered MP4 URL. Assets (screen recording, still, wallpaper) come from POST /v3/assets/direct-uploads — pass the resulting URL in the matching *_url field. operationId: createCustomAgentVideo parameters: - name: agent_id in: path required: true schema: type: string description: Custom-agent id (e.g. `chiron`). - $ref: '#/components/parameters/IdempotencyKey' requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/CustomAgentVideoCreateRequest' responses: '202': description: Accepted — submission acknowledged; poll for completion. content: application/json: schema: type: object properties: data: $ref: '#/components/schemas/CustomAgentVideoCreateResponse' '400': description: Invalid request parameters content: application/json: schema: type: object properties: error: $ref: '#/components/schemas/StandardAPIError' '401': description: Authentication failed content: application/json: schema: type: object properties: error: $ref: '#/components/schemas/StandardAPIError' example: error: code: unauthorized message: Invalid or expired API key. Verify your x-api-key header. param: null doc_url: null '404': description: Resource not found content: application/json: schema: type: object properties: error: $ref: '#/components/schemas/StandardAPIError' '409': $ref: '#/components/responses/IdempotencyInProgress' '429': description: Rate limit exceeded content: application/json: schema: type: object properties: error: $ref: '#/components/schemas/StandardAPIError' example: error: code: rate_limit_exceeded message: >- Too many requests. Retry after the duration specified in the Retry-After header. param: null doc_url: null headers: Retry-After: description: Seconds to wait before retrying schema: type: integer security: - ApiKeyAuth: [] - BearerAuth: [] components: parameters: IdempotencyKey: name: Idempotency-Key in: header required: false description: >- Optional client-supplied key for safely retrying mutations. Subsequent calls within 24 hours that share this key replay the original response — even if the request body differs slightly (a warning is logged). A retry that arrives while the original is still in flight gets a 409 `request_in_progress`. Keys must be 1–255 characters from `[A-Za-z0-9_:.-]`; a UUID is a safe default. Scope is per-endpoint and per-resource: the same key on a different route or path parameter is independent. schema: type: string pattern: ^[A-Za-z0-9_\-:.]{1,255}$ maxLength: 255 minLength: 1 example: 550e8400-e29b-41d4-a716-446655440000 schemas: CustomAgentVideoCreateRequest: description: >- Body for POST /v3/custom-agents/{agent_id}/videos. Assets (screen recording, still, wallpaper, presenter background) come from the caller — upload via `POST /v3/assets/direct-uploads`, then pass the resulting URL in the matching `*_url` field here. This endpoint does NOT accept multipart file uploads. properties: topic: description: What the video should be about. maxLength: 512 minLength: 1 title: Topic type: string lane: anyOf: - enum: - mac - iphone - watch type: string - type: 'null' default: null description: Device lane. Agent infers from the topic when omitted. title: Lane wallpaper: anyOf: - maxLength: 256 type: string - type: 'null' default: null description: >- `neo-green` / `neo-purple` / `neo-pink` / `wwdc26`, or a user-supplied HTTP(S) URL. title: Wallpaper avatar_id: anyOf: - maxLength: 128 type: string - type: 'null' default: null description: HeyGen avatar id for the on-camera presenter. title: Avatar Id avatar_still_url: anyOf: - maxLength: 1024 type: string - type: 'null' default: null description: >- URL of a still image (from `/v3/assets/direct-uploads`) for talking-photo inference. title: Avatar Still Url voice_id: anyOf: - maxLength: 128 type: string - type: 'null' default: null description: Voice id for narration (HeyGen or ElevenLabs). title: Voice Id watch_model: anyOf: - maxLength: 128 type: string - type: 'null' default: null description: 'Watch lane only: ` + ` selector.' title: Watch Model script: anyOf: - maxLength: 4096 type: string - type: 'null' default: null description: Verbatim voice-over script; agent generates one when omitted. title: Script screen_recording_url: anyOf: - maxLength: 2048 type: string - type: 'null' default: null description: >- URL of a screen-recording MP4 (from `/v3/assets/direct-uploads` or your own S3). title: Screen Recording Url presenter_background_url: anyOf: - maxLength: 2048 type: string - type: 'null' default: null description: URL of an image to composite behind the matted avatar. title: Presenter Background Url presenter_background_video_url: anyOf: - maxLength: 2048 type: string - type: 'null' default: null description: URL of a looping video to composite behind the matted avatar. title: Presenter Background Video Url required: - topic title: CustomAgentVideoCreateRequest type: object CustomAgentVideoCreateResponse: description: 202 response body for POST /v3/custom-agents/{agent_id}/videos. properties: video_id: description: Opaque id; poll GET /v3/custom-agents/{agent_id}/videos/{video_id}. title: Video Id type: string status: default: RUNNING description: Initial workflow status. title: Status type: string required: - video_id title: CustomAgentVideoCreateResponse type: object StandardAPIError: type: object properties: code: type: string description: Machine-readable error code example: invalid_parameter message: type: string description: Human-readable error message example: Video not found param: type: - string - 'null' description: Which request field caused the error doc_url: type: - string - 'null' description: Link to error documentation errors: type: array description: >- Per-item error details for batch/multi-node failures (e.g. graph compilation errors by node). items: $ref: '#/components/schemas/StandardAPIErrorDetail' required: - code - message StandardAPIErrorDetail: type: object properties: code: type: string description: Machine-readable error code example: unknown_node_type message: type: string description: Human-readable error message example: Unknown node type node_id: type: string description: Graph node id this error pertains to, if applicable port: type: string description: Port name on the node this error pertains to, if applicable path: type: string description: Field path within the item this error pertains to, if applicable required: - code - message responses: IdempotencyInProgress: description: >- A prior request with this Idempotency-Key is still in progress. Wait for the original request to complete, then retry. content: application/json: schema: type: object properties: error: $ref: '#/components/schemas/StandardAPIError' example: error: code: request_in_progress message: >- A request with this Idempotency-Key is already in progress. Retry shortly. param: null doc_url: null securitySchemes: ApiKeyAuth: type: apiKey in: header name: x-api-key description: HeyGen API key. Obtain from your HeyGen dashboard. BearerAuth: type: http scheme: bearer description: OAuth2 bearer token. ````