ThunderPhone

Quick answers

How does Zeus differ from using Claude Code or other AI coding assistants for voice agents?

Claude Code and similar tools are significantly worse at configuring voice agents because they were trained heavily on text and code data but far less on audio data. The knowledge for optimizing voice AI performance is scarce and sometimes misleading on the internet, leading these tools to blindly follow incorrect information. Unlike coding which has inherent test signals, voice AI requires specialized domain knowledge that general coding assistants lack.

Why does ThunderPhone use multiple models instead of a single pipeline?

A single three-step pipeline (transcription to text, text to LLM response, response to speech) has fundamental problems: transcription mistakes cannot be recovered from, there's a tradeoff between fast LLMs that make mistakes and slow ones that delay responses, and turn-based processing makes conversations unnatural. ThunderPhone runs multiple transcription models, combines fast and slow LLMs, and pipes audio directly to language models to overcome these limitations.

What does Zeus cost and when will it be paid?

Zeus is free during the beta period while it is new. The company plans to later release a light version that stays free, paid plans for the full Zeus, and the option to bring your own OpenAI or Anthropic API key.

How are voice quality and cost balanced?

Voices trade off naturalness against stability: more natural-sounding voices are more prone to mispronunciations and hallucinations on numbers and letters. Platform voices from Inworld cost almost nothing (~0.2¢/min), while premium voices from Cartesia and ElevenLabs add a few cents per minute but sound more natural. Zeus helps you pick the right tradeoff for your use case.

How can I import an existing voice agent to ThunderPhone?

Zeus enables one-click importing of voice agents from Vapi, Retell, Bland, or ElevenLabs, with the AI handling the import end to end. You can also create agents from scratch by describing your business needs, importing call-center recordings and scripts, or importing existing SOPs.