> ## Documentation Index > Fetch the complete documentation index at: https://docs.tavus.io/llms.txt > Use this file to discover all available pages before exploring further. # Overview > Define how your persona behaves, responds, and speaks by configuring layers and pipeline modes. Personas are the 'character' or 'AI agent personality' and contain all of the settings and configuration for that character or agent. For example, you can create a persona for 'Tim the sales agent' or 'Rob the interviewer'. Personas combine identity, contextual knowledge, and CVI pipeline configuration to create a real-time conversational agent with a distinct behavior, voice, and response style. They are the main place you configure **[CVI](/sections/conversational-video-interface/overview-cvi)** behavior before you start a **[Conversation](/sections/conversational-video-interface/conversation/overview)**. **At a glance** * **Persona** — The agent’s identity (name, voice, behavior) plus **pipeline mode**, **default replica**, **layers**, **documents** (Knowledge Base), **objectives**, and **guardrails**. * **Relationship to CVI** — Personas hold the settings that drive a real-time CVI session; see the **[What is CVI?](/sections/conversational-video-interface/overview-cvi)** for the full stack (WebRTC, layers, Phoenix, and latency characteristics on the default path). * **Layers (order of guides below)** — Perception → STT → Conversational Flow → LLM → TTS; each has its own configuration page. ## Persona Customization Options Each persona includes configurable fields. Here's what you can customize: * **Persona Name**: Display name shown when the replica joins a call. * **System Prompt**: Instructions sent to the language model to shape the replica's tone, personality, and behavior. * **Pipeline mode**: Controls which CVI pipeline layers are active and how input/output flows through the system. See [Pipeline modes](/sections/conversational-video-interface/quickstart/pipeline-modes) for how the full pipeline, Echo, integrations, and custom LLM paths differ. * **Default Replica**: Sets the digital human associated with the persona. * **Layers**: Perception, STT, conversational flow, LLM, and TTS—each processes part of the interaction and can be tuned independently (see [Layers](#layers) below). * **Documents**: A set of documents that the persona has access to via the **Knowledge Base** (retrieval-augmented generation, RAG). * **Objectives**: The goal-oriented instructions your persona will adhere to throughout the conversation. * **Guardrails**: Conversational boundaries that can be used to strictly enforce desired behavior. ## Objectives & Guardrails Provide your persona with robust workflow management tools, curated to your use case The sequence of goals your persona will work to achieve throughout the conversation—for example gathering a piece of information from the user. Conversational boundaries that can be used to strictly enforce desired behavior. ## Layers Explore our in-depth guides to customize each layer to fit your specific use case: Defines how the persona interprets visual input like facial expressions and gestures. Transcribes user speech into text using the configured speech-to-text engine. Controls turn-taking, interruption handling, and active listening behavior for natural conversations. Generates persona responses using a language model. Supports Tavus-hosted or custom LLMs. Converts text responses into speech using Tavus or supported third-party TTS engines.