> ## 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 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.. ## 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. * **Default Replica**: Sets the digital human associated with the persona. * **Layers**: Each layer in the pipeline processes a different part of the conversation. Layers can be configured individually to tailor input/output behavior to your application needs. * **Documents**: A set of documents that the persona has access to via Retrieval Augmented Generation. * **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 to throughout the conversation - for example gathering a piece of information from the user. Conversational boundaries that can be used to strictly enforce desired behavior. ## Layer 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. ## Pipeline Mode Tavus provides several pipeline modes, each with preconfigured layers tailored to specific use cases: ### Full Pipeline Mode (Default & Recommended)

The default and recommended end-to-end configuration optimized for real-time conversation. All CVI layers are active and customizable. * Lowest latency * Best for natural humanlike interactions We offer a selection of optimized LLMs including **Llama 3.3 and OpenAI models** that are fully optimized for the full pipeline mode. ### Custom LLM / Bring Your Own Logic

Use this mode to integrate a custom LLM or a specialized backend for interpreting transcripts and generating responses. * Adds latency due to external processing * Does **not** require an actual LLM—any endpoint that returns a compatible chat completion format can be used Built with [Mintlify](https://mintlify.com).