vocametrix
The Vocametrix server provides a comprehensive suite of clinical voice analysis, speech assessment, and AI-powered therapy planning tools for speech-language pathologists and voice professionals.
Voice Quality & Acoustic Analysis
AVQI, DSI – Overall dysphonia severity and Dysphonia Severity Index with age/gender norms
CPP/CPPS – Cepstral Peak Prominence for breathiness/hoarseness detection
HNR – Multi-band Harmonics-to-Noise Ratio
Jitter & Shimmer – Period and amplitude perturbation
Voice Range Profile – Frequency and intensity range from glissando recordings
Spectral Analysis – Spectral tilt, slope, center of gravity, formant energy
Formants (F1–F4) – Vowel space analysis
S/Z Ratio, GNE, H1–H2, ABI – Vocal fold pathology indicators and breathiness measures
Voice Dynamics – Dynamic range, pitch-intensity correlation, vocal stability
Prosody Similarity – Compare prosodic patterns between recordings
Speech & Pronunciation
Pronunciation Assessment – Phoneme-level scoring with per-word breakdowns (30+ locales), optionally combined with per-word F0 contours
Transcription – Streaming ASR with word-level timing
Text-to-Speech – Azure Neural voices; ElevenLabs TTS with per-character timing for lip-sync/subtitles
Audio Measures
Sound Level – dB SPL and intensity statistics over time
eGeMAPS – 88 acoustic features for ML-based voice pathology classification
Phoneme Detection – Detect phonemes in French and Estonian audio
Stuttering Classification – Dysfluency pattern classification with severity scoring
AI Agents
Clinical Interpretation – Translate raw voice metrics into clinician-readable severity reports and recommendations
Exercise & Word List Generation – Personalized therapy exercises and phoneme-targeted word lists by pathology/profile
Adaptive Exercises – Adapted for specific learner profiles (ADHD, dyslexia, autism, etc.)
Therapist Chat – Conversational AI speech-language therapist adapting to therapist/patient/parent roles
French IPA Conversion, Spelling Interpretation, Syntax Checking, Vocabulary Tutor – Language support tools with spaced repetition
Therapy Planning
Generate AI therapy plans asynchronously from session audio, poll for status, retrieve completed plans, and manage human-in-the-loop approval (approve/modify/reject)
Workflow Tools
Full Voice Assessment – Run AVQI + CPP + HNR + jitter/shimmer + spectral in a single call
Batch Pronunciation – Assess multiple WAV files against a reference text
Full Therapy Workflow – End-to-end generate → poll → fetch → approval pipeline
Audio Ingestion – Upload WAV files (base64) or ingest public HTTPS WAV URLs for stable blob references
@vocametrix/mcp-server
Official Model Context Protocol server for the Vocametrix voice analysis API.
Gives any MCP-compatible AI assistant (Claude Desktop, Cursor, Cline, etc.) direct access to clinical voice metrics, pronunciation assessment, speech transcription, and AI-powered therapy planning.
Quick start
Claude Desktop
Add to ~/Library/Application Support/Claude/claude_desktop_config.json (macOS) or %APPDATA%\Claude\claude_desktop_config.json (Windows):
{
"mcpServers": {
"vocametrix": {
"command": "npx",
"args": ["-y", "@vocametrix/mcp-server"],
"env": {
"VOCAMETRIX_API_KEY": "your-api-key-here"
}
}
}
}Get an API key at vocametrix.com/registration. Free trial: 5 minutes of analysis.
Related MCP server: elevenlabs-mcp
Tools
Voice quality (acoustic)
Tool | Description |
| Acoustic Voice Quality Index (AVQI) — overall dysphonia severity |
| Dysphonia Severity Index (DSI) |
| Cepstral Peak Prominence — breathiness, hoarseness |
| Harmonics-to-Noise Ratio (multi-band) |
| Period and amplitude perturbation |
| Voice Range Profile |
| Prosody similarity between two utterances |
Advanced voice analysis
Tool | Description |
| Spectral tilt, slope, and formant energy |
| Formant frequencies F1–F4 |
| S/Z phonation ratio |
| Glottal-to-Noise Excitation |
| H1–H2 harmonic difference |
| Acoustic Breathiness Index |
| Dynamic range and fundamental frequency statistics |
Ingestion utilities
Tool | Description |
| Upload a WAV file (base64) → returns a stable blobUrl |
| Ingest a public HTTPS WAV URL → returns a stable blobUrl |
Speech and pronunciation
Tool | Description |
| Phoneme-level pronunciation scoring |
| Pronunciation + pitch analysis combined |
| Streaming ASR transcription with progress |
| Text-to-speech synthesis |
| TTS with word-level timing data |
Audio measures
Tool | Description |
| dB SPL and intensity statistics |
| Extended Geneva Minimalistic Acoustic Parameter Set |
| Phoneme presence/absence detection |
| Dysfluency classification |
AI agents
Tool | Description |
| Clinical interpretation of voice metrics |
| Personalized voice/speech exercise generation |
| Target word list generation for therapy |
| Conversational AI speech-language therapist |
| French text → IPA phonetic transcription |
| Spelling correction agent |
| Syntax checking agent |
| Vocabulary tutoring agent |
| Adaptive exercise generation |
Therapy planning
Tool | Description |
| Generate an AI therapy plan |
| Poll therapy plan generation status |
| Fetch completed therapy plan |
| Approve a therapy plan |
Workflow tools
Tool | Description |
| Parallel AVQI + CPP + HNR + jitter/shimmer + spectral |
| Assess a folder of WAV files |
| Generate → poll → fetch → approval flow |
Resources
vocametrix://docs/api— API quick reference (auth, rate limits, audio requirements, error codes)vocametrix://thresholds/{metric}— Clinical reference thresholds foravqi,dsi,cpp,hnr,jitter-shimmer,gne
Prompts
interpret_voice_assessment— Generate a clinical SLP-style interpretation report from assessment JSONcompare_pre_post_therapy— Quantified pre/post therapy narrative with metric-by-metric comparisongenerate_session_report— SOAP-format progress note from pronunciation assessment data
Audio requirements
Format: WAV (16-bit PCM recommended)
Sustained vowel tasks: 3+ seconds of /a/ phonation
Connected speech tasks: 5–30 seconds of read passage
Minimum sampling rate: 16 kHz
How to pass audio to a tool
The audioPath parameter accepts several input types, but which ones are valid depends on how the MCP server is running:
Input | Hosted / remote server | Stdio / local server ( |
| ✅ recommended | ✅ |
Public | ✅ | ✅ |
Public URL via | ✅ recommended for URL inputs | ✅ |
| ✅ | ✅ |
Raw base64 string (≥ 512 chars) | ✅ | ✅ |
Absolute local path ( | ❌ rejected | ⚠️ requires |
For chat clients that attach audio in the conversation (Claude.ai web/mobile, etc.), the LLM cannot pass an absolute path to a hosted server — it must call vocametrix_upload_audio first with the file content base64-encoded, then pass the returned blobUrl as audioPath to any analysis tool. The MCP descriptions guide the LLM toward this workflow automatically.
For stdio/local deployments where the MCP runs on the user's own machine, set VOCAMETRIX_MCP_LOCAL_FS=1 to allow analysis tools to read absolute local paths directly — convenient for batch processing of files already on disk.
Environment variables
Variable | Required | Description |
| Yes | Your Vocametrix API key |
| No | Set to |
Development
git clone https://github.com/pmarmaroli/vocametrix-mcp.git
cd vocametrix-mcp
npm install
npm run build
npm test # run unit tests
npm run inspector # test with MCP InspectorMCP Registry
Listed in the official MCP Registry under io.github.pmarmaroli/vocametrix-mcp. Available for one-click installation in MCP-compatible clients (Claude Desktop, Cursor, Zed, Windsurf, and more).
Related projects
The Vocametrix ecosystem:
📘 Vocametrix API documentation — full reference for the underlying REST API powering this MCP server.
📐 OpenAPI 3.1 specification — machine-readable schema for all 48 endpoints.
🐍 vocametrix-python — official Python SDK if you want direct API access from Python (
pip install vocametrix).🟦 vocametrix-js — official TypeScript / JavaScript SDK used internally by this MCP server (
npm install vocametrix).
License
MIT — see LICENSE
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