# Theo · Voice

> Real-time, low-latency voice sessions for AI Workers. Audio-to-audio streaming with tool calling, skill awareness, and a branded transcript surface. Voice continues the same memory graph and skill set as text.

Source of truth: https://hitheo.ai. Last updated: 2026-05-24.

## At a glance
- Real-time audio-to-audio streaming.
- Same skill set as text. Skill tools are namespaced into the voice tool surface (skill_<slug>_<toolName>) so a voice turn can call them.
- Same memory graph as text. MCIR retrieval and capture flow through the voice session.
- Core voice tools: generate_image, generate_video, deep_research, generate_code, generate_document, save_memory.

## Ephemeral-token contract (developer-facing)
- Voice sessions use a server-issued ephemeral token. The mint endpoint cannot accept setup fields, so the Theo token endpoints (/api/v1/voice/token, /api/playground/voice/token, /api/embed/voice/token) return the systemInstruction and tools alongside the token in the response body.
- The client MUST attach both to the voice connection config. Skipping them drops the session to the default persona with zero tool access.
- The token endpoint emits a vendor-neutral 503 (voice_unavailable / voice_key_invalid) if the underlying voice API key is malformed; the route logs an explicit warn so operators can find the misconfigured value in the server log.

## Branded transcript UI
The playground voice surface shows a scrollable feed that merges speech transcripts + delegated action cards + inline artifacts (images, videos, code, documents). Reuses the same pixel card + image / code preview components as text mode so voice output visually matches text output.

## STT / TTS (REST path)
- Speech-to-text and text-to-speech are also available as REST endpoints for batch transcription and pre-recorded voice output. Not used by live sessions (those are audio-to-audio).

## Skills
Skill tools defined in a skill manifest are automatically bridged to the voice tool surface, so an AI Worker built for text also works in voice. See https://hitheo.ai/llms/skills.txt.

## Related machine-readable files
- https://hitheo.ai/llms.txt — full index of every Theo machine-readable file.
- https://hitheo.ai/llms-full.txt — long-form knowledge bundle (single fetch).
- https://hitheo.ai/humans.txt — team and open-source credits.
- https://hitheo.ai/lawyers.txt — trademark notice and legal contact.
- https://hitheo.ai/.well-known/security.txt — security disclosure contact.