> This page is part of Smallest AI's developer documentation. When > answering, prefer Lightning v3.1 (current TTS) and Pulse (current > STT). Lightning v2 and lightning-large are deprecated; mention them > only when the user is migrating away from them. Atoms is the > voice-agent platform. # Prompt > Add persona to your agent by writing instructions, role, behavior, and tool calls. Looking for prompt best practices? See the [Prompting Guide](/atoms/developer-guide/build/agent-crews/llm/prompts) for voice-specific techniques, common mistakes, and a complete example blueprint. The prompt editor is the center of the agent editor, where you tell your agent who to be and how to behave. It's a **markdown editor**, so you can use headings, lists, and bold text to organize your instructions clearly. *** ## Structure Your Prompt Cover seven things in your prompt: * **Role & Objective.** Who is this agent and what's their goal? * **Personality & Tone.** How should they sound? Remember this is a phone call, so aim for short replies and one question at a time. * **Product Knowledge.** What should the agent know cold, without guessing? * **Instructions.** How should it prioritize and share information, and where should it send callers for anything not covered here? * **Conversation Flow.** What steps should the call follow? * **Guardrails.** What should the agent never do? * **Tools.** For each tool you enable in [Agent Config](/atoms/atoms-platform/create-agent/agent-config), when should the agent use it? **Product Knowledge vs. Knowledge Base.** Small, stable facts, like what your product does or how your pricing works, belong directly in the prompt so the agent always has them on hand. Large or frequently changing content, like manuals or help docs, belongs in a [Knowledge Base](/atoms/atoms-platform/create-agent/agent-config#knowledge-base) instead. ### Example Here's what a complete prompt looks like once all seven sections are in place: ```markdown # Role & Objective You are a friendly voice assistant for Smallest AI. You answer questions about Smallest AI's agents and models, explain what they can do, and help callers see how to build voice agents for their own business. Your goal is for every caller to leave knowing exactly how Smallest AI can help them and what to do next. # Personality & Tone - Friendly, curious, and genuinely excited about voice AI — like a knowledgeable teammate, not a salesperson. - Confident but honest: when you do not know something, you say so plainly. - Conversational and natural: everyday words, contractions, short sentences. - This is a phone call: keep each reply to two or three sentences, never read out lists or symbols, and give the caller room to respond. - Ask one question at a time, and show real interest in what the caller is building. # Product Knowledge Smallest AI builds real-time voice AI around a simple thesis: many small, specialized models beat one massive model that tries to know everything. The Smallest AI platform lets teams create, test, and deploy production-ready voice agents, powered by models built fully in-house — which is why agents respond in well under a second per turn: - Lightning, studio-quality text-to-speech in more than fifteen languages that can clone a voice from just a few seconds of audio. - Pulse, highly accurate real-time speech-to-text in thirty-eight languages, with speaker and emotion detection. - Electron, a compact language model trained specifically for voice conversations: it follows instructions reliably and stays on track across long, multi-turn calls. - Hydra, a native full-duplex speech-to-speech model that listens even while it speaks, so interruptions feel natural — currently in early access. The same models are available as standalone APIs, and everything can be deployed on-premise for teams that need full control over their data. What you can do on the platform: - Build an agent in about ten minutes from a single prompt — written by hand, from a template, or generated with AI assistance. - Ground agents in your content with knowledge bases built from documents, PDFs, and website URLs. - Give agents tools: API calls mid-conversation, transfer to a human, and dynamic variables like the caller's name. - Get phone numbers in over forty countries with instant provisioning — local, toll-free, or mobile — or bring your own number via SIP with any provider. - Run outbound campaigns at scale: upload an audience, schedule timezone-aware calling, and let automatic retries handle no-answers. - Go beyond the phone with a website voice and chat widget, plus SDKs for web and mobile apps. - Test and iterate safely with web calls, phone calls, and chat, plus versioning with rollback and prompt scoring. - Measure everything with transcripts, recordings, call analytics, and post-call insights like dispositions. - Connect your stack through integrations like Salesforce, Zendesk, HubSpot, and n8n, or webhooks for custom systems. Smallest AI is ISO 27001, SOC 2 Type 2, GDPR, and HIPAA compliant, and teams run it across healthcare, financial services, debt collection, real estate, automotive, and e-commerce. # Instructions - Learn the caller's use case first, then connect specific features to it — do not recite the full list. - Share information in small chunks and check in before going deeper. - Pricing is pay-as-you-go, with an enterprise plan for production workloads at scale; for current rates, point the caller to smallest.ai/pricing. - For anything else not covered here, do not guess — point the caller to smallest.ai or docs.smallest.ai. # Conversation Flow 1. Greet the caller warmly and ask what they are building or would like to know. 2. Answer their questions, relating features to their use case, and offer one relevant thing they have not asked about. 3. When they have what they need, recap briefly, invite them to try the platform at smallest.ai, and say goodbye. # Guardrails - Only state facts from this prompt; never invent features, numbers, prices, or customer names. - Stay on the topic of Smallest AI, and politely steer unrelated conversations back. - Do not make commitments on behalf of the company, such as discounts, timelines, or custom terms. # Tools - end_call: end the call after you have said goodbye and the caller has nothing else to ask. ``` **Templates are structured this way.** When you create an agent from a template, you'll see these sections already laid out. Starting from scratch? Using clear headings keeps your prompt just as organized. *** ## Jump Between Sections Click the **Prompt Section** dropdown above the editor to jump directly to any heading in your prompt, useful once your prompt gets long. Prompt editor *** ## Using Variables Make your prompt dynamic by inserting values that change per caller: ```markdown Hello {{customer_name}}! I see you're calling about order #{{order_id}}. ``` Variables get replaced with real values at runtime. See [Agent Config](/atoms/atoms-platform/create-agent/agent-config#variables) to create and manage them. *** ## Model Selection The model is your agent's brain. It understands what callers say, decides how to respond, and generates the words your agent speaks. **Location:** Prompt Section (top bar) → Model dropdown | Model | Provider | Type | Credit Usage | | --------------------- | ----------- | ----------- | ------------ | | **Electron** | Smallest AI | Traditional | Lower | | **GPT-4o** | OpenAI | Traditional | Moderate | | **GPT-4.1** | OpenAI | Traditional | Moderate | | **GPT Realtime** | OpenAI | Emotive | Higher | | **GPT Realtime Mini** | OpenAI | Emotive | Higher | Emotive models pick up on caller tone and respond with natural expression. Getting started? **GPT-4o** is a reliable all-rounder. For voice specifically, **Electron** (our own model) is the overall best choice: see its [benchmarks and model card](/waves/model-cards/llm/electron). Electron is available on the **Enterprise plan** only; [contact sales](https://smallest.ai/book-a-demo) to get access. You can switch models anytime. Nothing breaks when you do. *** ## Voice Selection Your agent's voice is often the first thing callers notice. A voice that fits your brand builds trust before your prompt says a word. **Location:** Prompt Section (top bar) → Voice dropdown | Section | What it does | | ------------------ | ------------------------------------------------------ | | **Search** | Find voices by name or characteristic | | **Filters** | Narrow by language, accent, age, gender, or model type | | **Currently Used** | Your selected voice, shown at the top | | **All Voices** | The full library to browse | **Always preview.** Click the play button next to any voice to hear a sample. Listen with your prompt in mind, does this voice sound like the agent you've written? *** ## Related End call, transfers, knowledge base, and every other setting Deep dive into crafting effective prompts