Generate natural-sounding speech audio from text. Use this when the user wants to: hear text read aloud, create narration or voiceover, generate voice audio, preview how text sounds when spoken, or convert any writing into spoken audio. Supports 31 languages including Korean, English, and Japanese. There is no text-length limit: long text is automatically split (auto-chunked) by the service, and credit usage and latency scale with the length of the text. Set output_mode ('files', 'resources', or 'both') to control how audio is returned, and autoplay=true to play it back on macOS. These per-call parameters REPLACE the removed SUPERTONE_MCP_OUTPUT_MODE and SUPERTONE_MCP_AUTOPLAY environment variables; autoplay now defaults to false. A default voice is already configured -- just call this tool directly. Only call search_voice if the user explicitly asks to change or browse voices.

Search the Supertone voice catalog. Filters are optional and combined with AND semantics: name, description, language, gender, age, use_case, style, model. With no filters, returns the full catalog (the v0.1 list_voices behavior). The output is a numbered plain-text list; when any filter is set, the first line shows "Filters applied: ...".

Fetch full detail for a single voice by voice_id. Returns name, description, age, gender, use_cases, languages, styles, supported models, sample count, and thumbnail URL. Use preview_voice to get the actual sample audio URLs.

Returns the remaining Supertone credit balance for the current API key. Use this before long TTS calls to confirm you have enough characters left.

Fetch sample audio URLs for a voice. Optionally filter samples by language, style, and model. Returns one URL per matching sample. v0.2 does NOT play the audio locally; pass the URL to your client to listen.

Predict the expected output audio duration in seconds for a given text WITHOUT producing any audio file. Accepts the same parameters as text_to_speech. There is no text-length limit: long text is automatically split (auto-chunked), and credit usage and latency scale with the length of the text. Use this to estimate credit cost before synthesizing — credit usage is proportional to the predicted duration.

Create a custom voice from a single local audio file. Constraints: WAV or MP3 only, max 3MB, exactly one file. The returned voice_id can be used immediately in text_to_speech. Path supports ~ expansion (e.g., "~/sample.wav").

List custom (cloned) voices created by this API key. Optional name and description filters perform partial matching. Pagination is handled internally; v0.2 returns the SDK default page.

Update the name and/or description of an existing custom voice. At least one of name or description must be provided.

Permanently delete a custom (cloned) voice. THIS IS IRREVERSIBLE — once deleted, the voice cannot be recovered and any saved voice_id referencing it will stop working. Confirm with the user before calling.

Fetch the detail of a single custom (cloned) voice by voice_id. Returns the voice's name and description. Use search_custom_voice to list custom voices and find a voice_id.

Retrieve recent TTS API usage history for the current API key. Returns a plain-text summary broken down by time period, showing the minutes used (and, when available, the voice and model) in each period. Takes no parameters — it reports usage over a recent default window. Use this to review how much synthesis has been consumed.

Retrieve recent usage for a single voice by voice_id. Returns a plain-text summary of the voice's per-day minutes used over a recent default window. Use search_voice or search_custom_voice to find a voice_id.

Merge two or more local audio files into a single file using ffmpeg. Supports plain concatenation, silence-gap insertion between clips (gap_ms), or crossfade blending (crossfade_ms). gap_ms and crossfade_ms are mutually exclusive. Output format is auto-detected from the inputs (all-same-ext -> that ext; mixed -> mp3) or overridden via output_format. Use this to stitch multiple text_to_speech outputs into one deliverable.