Voice Engines
No single engine is right for every character or every machine — a catalogue voice, a cloned sample, and a designed voice each solve a different problem, so Castwright supports four TTS engines and lets you pick per character. They surface in two different places: Kokoro, Coqui, and Qwen are local models with disk/VRAM residency, managed from Admin → Model Manager (each row shows install state, size, and — once usable — a Load/Unload pill; see The Model Control Pill). Gemini has no local model to manage — it's a cloud voice catalog you pick from directly on a character, in the Profile Drawer's "Model voice" picker.
See Installing Castwright for setup steps for each.
Ships as a standard engine — installs with the Python sidecar — and every character carries a Kokoro preset as a fallback, so a book still generates even before Qwen or Coqui are set up. Below, Kokoro's row in Model Manager: fully installed, DEFAULT + FALLBACK badges, verified integrity, loaded and ready with a Stop action.
An optional add-on (not installed by default) — install it from Admin → Model Manager → Optional add-ons → Coqui → Install. Once the package is present, Coqui gets the same idle/loading/ready pill as any other engine (see The Model Control Pill). Below, Coqui's row once installed: Installed badge, Load model pill, and an Update toggle for reinstalling the package.
Qwen is the flagship per-character engine — the one the cast's designed voices actually use. It ships a Base tier (0.6B, the everyday default, and a higher-quality 1.7B) plus a VoiceDesign model used transiently while designing a bespoke voice — each its own Model Manager row, loaded and unloaded independently. Below, the Base (0.6B) row installed and idle: an unpinned integrity chip (its weights aren't a single fixed-file release, so size-based integrity pinning doesn't apply the way it does for Kokoro), Installed badge, and a Load model pill.
Gemini isn't a local model, so it has no Model Manager row — there's nothing to load or unload. It shows up instead as a voice family in the Voice Library and as one of the tabs in a character's Model voice picker (Profile Drawer → Voice profile), alongside Coqui and Kokoro — those preset tabs only render once that character's engine is set to something other than Qwen; a Qwen-engine character designs a bespoke voice instead (see Designing a Voice) and never sees this picker. Below, "Charon" — a Gemini voice reused across two cast members in The Hollow Tide series — with Audition base voice and Rebaseline the series actions.
Next: The Model Control Pill.