> ## Documentation Index > Fetch the complete documentation index at: https://docs.orbit.devotel.io/llms.txt > Use this file to discover all available pages before exploring further. # Resolve a sticky A/B variant assignment > Assign a contact to a variant of the agent's active A/B experiment and return the variant plus the prompt version to apply. The assignment is sticky per contact — the first call rolls the variant using the adaptive traffic split and records an impression, and later calls return the same variant without re-rolling. Pass `dry_run: true` to preview the would-be variant without persisting. Requires the owner, admin, or developer role. ## OpenAPI ````yaml /openapi.yaml post /api/v1/agents/{id}/ab-assignments openapi: 3.1.0 info: title: Devotel CPaaS API description: Orbit by Devotel — Communications Platform as a Service API version: 1.0.0 contact: name: Devotel url: https://devotel.io email: support@devotel.io license: name: Proprietary servers: - url: https://api.orbit.devotel.io description: Production security: - Bearer: [] - ApiKey: [] tags: - name: Messages description: >- Send and manage messages across all channels (SMS, WhatsApp, RCS, Email, Viber, etc.) - name: Fax description: >- List and track fax (MMS/T.38) transmissions on Telnyx-backed fax numbers (sending flows through the Messaging API) - name: Agents description: AI agent creation, configuration, and execution - name: Voice description: Voice calls, IVR, conferencing, and SIP trunking - name: OnCall description: On-call rotations and escalation policy planning for incident alerting - name: Webhooks description: Webhook endpoint management and delivery logs - name: Numbers description: Phone number search, provisioning, and configuration - name: Brand Identity description: >- Unified cross-channel brand trust posture (10DLC, toll-free, WhatsApp, RCS, branded calling, number KYC) - name: Contacts description: Contact management, segmentation, and lifecycle tracking - name: Campaigns description: Marketing campaign orchestration and analytics - name: Flows description: Automation flow builder and execution engine - name: Templates description: Message template management and approval workflows - name: Settings description: Organization, channel, and user preference settings - name: Verify description: OTP generation and verification across channels - name: Push description: Push notification delivery via FCM and APNs - name: Integrations description: Third-party service connections and OAuth management - name: CDP description: >- Customer Data Platform — activation surface (CRM object sync, streaming destinations, ad-audience activation) - name: Files description: >- Server-to-server media upload, listing, retrieval, and deletion (signed-URL backed) - name: Commerce description: >- Omnichannel conversational-commerce — persistent cart + checkout state machine, channel-agnostic hosted pay-by-link, native WhatsApp checkout, and AP2-style agent payment mandates. - name: Sync description: >- Real-time shared-state primitive (Twilio Sync parity) — Documents, Maps, Lists, and ephemeral Streams, with change events relayed over the /api/v1/ws/sync WebSocket gateway - name: Risk description: >- Unified cross-channel Trust & Fraud risk scoring — fuses SMS-pumping, URL-reputation, Verify Fraud Guard, and Voice Biometrics signals into one composite verdict queryable before a send or a call. - name: Orby description: >- In-dashboard Orby operator assistant: streamed assistant turns, conversation threads, product knowledge-base search, and the tool-action approval gate. Available to signed-in operators only (dashboard session auth — API-key requests are rejected). paths: /api/v1/agents/{id}/ab-assignments: post: tags: - Agents summary: Resolve a sticky A/B variant assignment description: >- Assign a contact to a variant of the agent's active A/B experiment and return the variant plus the prompt version to apply. The assignment is sticky per contact — the first call rolls the variant using the adaptive traffic split and records an impression, and later calls return the same variant without re-rolling. Pass `dry_run: true` to preview the would-be variant without persisting. Requires the owner, admin, or developer role. parameters: - schema: type: string in: path name: id required: true description: Identifier of the agent running the experiment. requestBody: required: true content: application/json: schema: type: object required: - contact_id properties: contact_id: type: string description: Identifier of the contact to assign a variant to. conversation_id: type: string description: Optional conversation this assignment belongs to. dry_run: type: boolean default: false description: When true, return the would-be variant without persisting. example: contact_id: contact_7a1b2c3d conversation_id: conv_9f3c1a2b responses: '200': description: >- The resolved variant, or has_experiment=false when no experiment is active. content: application/json: schema: type: object properties: data: type: object properties: has_experiment: type: boolean experiment_id: type: string assignment_id: type: string variant: type: string enum: - a - b version_id: type: string conversion_metric: type: string effective_split_pct: type: number meta: $ref: '#/components/schemas/ResponseMeta' components: schemas: ResponseMeta: type: object required: - request_id - timestamp additionalProperties: false properties: request_id: type: string description: Unique request identifier (also returned as X-Request-Id header) timestamp: type: string format: date-time docs_url: type: string format: uri nullable: true securitySchemes: Bearer: type: http scheme: bearer bearerFormat: JWT description: Dashboard JWT token from Clerk ApiKey: type: apiKey name: X-API-Key in: header description: Server-to-server API key (dv_live_sk_*) ````