Let an agent split audio, train your voice and use it

An AI assistant or coding agent can split a song into stems, split the lead vocal from the backing vocals, or take noise or reverb out of a recording, free and with no account. With your NiceVois account connected, it can also train a private RVC v2 model, or use a voice in your library to convert a vocal and return both the normal RVC and NiceVois cleaned versions.

Machine-readable entry points

The free audio tools need no sign-in at all, and agents can read the training and conversion requirements without signing in. Account state, private voices, training jobs and conversions require OAuth account linking.

Free audio tools, no account

The same four tools the website offers free, for an agent to run on a user’s file. No account, no API key, no sign-in. Input can be WAV, MP3, FLAC, M4A or OGG; the results come back as WAV, FLAC, MP3 or OGG.

1. Create the job with the tool, the file’s name and its exact size in bytes: MCP create_free_audio_job, or POST /api/agent/v1/audio-jobs. The length of the audio is optional; NiceVois measures the file itself.
2. Upload the file’s bytes with one HTTP PUT to the returned upload.url.
3. Check the job no more than every 10 seconds with get_free_audio_job, or GET its links.status. A song usually takes a few minutes.
4. When it is complete, save each file from its downloadUrl, which redirects to the audio, or give the user the links.

curl -s https://nicevois.com/api/agent/v1/audio-jobs \
  -H "content-type: application/json" \
  -d '{"tool":"split_lead_backing","fileName":"song.wav","sizeBytes":31457280}'
curl -T song.wav -H "content-type: application/octet-stream" "<upload.url>"
curl -s "<links.status>"
curl -L -o "song - Lead vocal.wav" "<outputs[0].downloadUrl>"

The job id returned at creation is the only key to the job and its files, so keep it private to the user it belongs to. An assistant that cannot read the user’s file or make HTTP requests should give the user the tool’s page from the table instead: the same job runs free in the browser.

Training contract

1. Call get_training_requirements, then get_training_account.
2. Inspect the audio and call quote_training. Tell the user the exact balance deduction, including any welcome credit, before creating anything.
3. If balance is required, show the returned private account link. Checkout through that link funds the same coding-agent identity. Verify the balance and continue the same request.
4. Create the job without repeating consent. Only if NiceVois reports CONSENT_REQUIRED, ask once for acceptance of the linked standing agreement and retry.
5. Upload the exact audio once, start training, and check no more than every 15 seconds. When complete, return clickable PTH, index, and ZIP links; when local file access is available, also save them to the user's normal Downloads folder.

Voice conversion contract

1. Call get_conversion_requirements, then inspect the attached source vocal.
2. Call list_voice_models and select a private trained or uploaded voice. If the user supplied a private .pth or complete model ZIP, prepare and upload it with create_voice_model_import, then list voices again.
3. Call create_voice_conversion with the selected voice, source filename, and requested pitch shift. Upload the vocal once to the returned private PUT URL.
4. Call get_voice_conversion no more than every 10 seconds and report the returned stage without inventing progress.
5. When complete, present NiceVois cleaned first and Normal RVC second. Call download_voice_conversion_output for the version the user wants. Each download uses that audio’s length; repeating the exact file requires confirmation.

Whole-song cover status

NiceVois runs a managed song-plus-voice cover pipeline on the website today. It trains or loads a permitted voice, separates the full song into instrumental, lead, and backing-vocal parts, converts the lead, restores consonants and breaths, and mixes the result back at the record's original balance. The one-step route is website-only for now, but an agent can do it in steps: split the song with the free split_lead_backing tool, convert the lead vocal, and give back the instrumental with backing vocals to go under it.

Free use and payment

The four audio tools are free for everyone, with no limit. For training, each connected account gets one free training, for up to 5 minutes of audio at up to 150 epochs. NiceVois quotes every training before upload, and the private browser handoff keeps purchases, models and training on one account.

What works today

The remote MCP and versioned REST API expose the four free audio tools, training and isolated-vocal conversion: discovery, OAuth account linking, private model selection and import, job progress, payment recovery for training, model artifact retrieval, and normal or cleaned conversion downloads. Whole-song cover creation remains a private preview and is represented as discovery metadata only.

About drag-and-drop chat

A coding agent that can read a local attachment and make authenticated HTTP requests can use this contract now. Normal chat clients still need a secure attachment handoff exposed to the NiceVois plugin. The submitted integration will add that supported handoff where the host permits it; this page does not claim universal drag-and-drop support.