Prosody Lens

Prosody Lens

Tool-backed prosody analysis for voice memos. Prosody means the measurable delivery layer of speech: pitch movement, loudness, rhythm, timing, pauses, stress, emphasis, and phrase contour.

This is not a clinical or diagnostic tool. It can describe delivery patterns and surface coaching observations, but it must not diagnose speech disorders, medical conditions, emotional state, or intent.

When To Use

Use this skill when the user:

• uploads an audio file and asks how the voice sounds
• asks for prosody, cadence, rhythm, pitch, emphasis, pauses, or vocal variety
• wants to identify or visualize prosodic patterns in speech/accent work
• provides a clip that is already known to contain a prosodic pattern
• wants a visual report of a voice memo
• wants to compare delivery across takes
• wants a repeatable process for speech, narration, teaching, presentation, or

voice-coaching feedback

Do not use this skill for transcript-only writing feedback unless no audio is available. Prosody analysis without acoustic data is mostly guesswork.

Dependencies

Required local tools:

• Python 3.9+
• numpy
• ffmpeg
• ffprobe

Optional higher-fidelity tools:

• Praat/Parselmouth for serious pitch, intensity, duration, and spectrogram work
• WhisperX or Montreal Forced Aligner for word/phoneme alignment
• openSMILE for standardized acoustic feature sets
• librosa and Plotly for richer future visualization work

No API key is required for the bundled analyzer. Hosted transcription tools such as Groq Whisper are optional and require explicit approval for the specific file.

Optional Praat setup:

python3 -m venv .venv
. .venv/bin/activate
python3 -m pip install -r requirements.txt -r requirements-praat.txt

Modes

| Mode | Invocation | Output | |------|------------|--------| | Analyze | "analyze this voice memo" / --analyze | Markdown report + JSON metrics | | Visualize | "visualize the prosody" / --viz | Interactive HTML report + Markdown; quiet-edge auto-focus when needed | | Visual Export | "visual only" / "download just the image" | Toggle a low-text visual view, choose Map/Card/Library layouts, show sparse non-overlapping transcript words as dot/connector/card callouts over smoothed presentation contours when available, and export the active PNG | | Compare | "compare these two takes" / --compare | Run one report per take, then synthesize differences | | Progression | "show progression over time" / --progression | Append/read trend records and compare stable metrics | | Pattern Discovery | "find prosodic patterns" / --patterns | Candidate contour patterns, repeat families, and pattern visuals | | Known Pattern | "visualize this known pattern" / --pattern-label | Label the exemplar, then show contour candidates and visual options | | Pattern Library | "build/match the pattern library" / --pattern-library | Save analyst-approved exemplars and match future clips against them | | Pattern Review | "review/approve/rename pattern candidates" | Use the HTML Pattern Review Workbench to export an approval/rejection JSON payload | | High Fidelity | "use Praat/DTW" / --pitch-method praat + --library-match-method dtw | Praat/Parselmouth pitch/intensity plus DTW exemplar matching | | Coach | "coach this delivery" / --coach | Analysis plus practical delivery suggestions |

Default mode is Analyze + Visualize when an audio file is present.

Recommended Workflow

1. Confirm input. Identify the audio file path, the speaker goal if given,

and whether the user supplied a script/transcript.

1. Run the analyzer.

python3 /scripts/prosody_analyze.py \
  /absolute/path/to/audio.ogg \
  --out-dir ./analysis/prosody/ \
  --pitch-method auto \
  --speaker speaker-1 \
  --goal clarity \
  --take-label baseline \
  --history ./analysis/prosody/prosody-history.jsonl

If the user provides an audio clip already identified as a prosodic pattern:

python3 /scripts/prosody_analyze.py \
  /absolute/path/to/pattern-clip.ogg \
  --out-dir ./analysis/prosody/ \
  --pattern-label "known rising terminal contour" \
  --pattern-notes "label supplied by analyst"

If the user wants to build or reuse a pattern library:

cp /references/pattern-library-starter.json ./analysis/prosody/pattern-library.json
python3 /scripts/prosody_analyze.py \
  /absolute/path/to/pattern-clip.ogg \
  --out-dir ./analysis/prosody/pattern-exemplar \
  --pattern-library ./analysis/prosody/pattern-library.json \
  --save-pattern-label "analyst-approved contour label" \
  --save-pattern-rank 1
python3 /scripts/prosody_analyze.py \
  /absolute/path/to/new-clip.ogg \
  --out-dir ./analysis/prosody/new-clip \
  --pattern-library ./analysis/prosody/pattern-library.json \
  --library-match-method hybrid

If the user supplied a transcript:

python3 /scripts/prosody_analyze.py \
  /absolute/path/to/audio.ogg \
  --transcript /absolute/path/to/transcript.txt \
  --out-dir ./analysis/prosody/

1. Read the outputs.

• report.md: delivery summary, listen-first moments, metrics, guardrails
• report.html: standalone visual report with embedded audio by default
• prosody.json: schema v0.5 metrics, synthesis, session, analyzer method,

trend metrics, pattern analysis, pattern-library matches, progression segments, and time series

• audio.wav: normalized mono WAV used for analysis unless --share-safe
• audio.mp3: browser-friendly playback copy embedded in report.html

unless --share-safe is used

• prosody-history.jsonl: optional compact longitudinal records when

--history is supplied

1. Answer in human terms. Translate metrics into useful observations:

"steady pacing with long pauses before key points", not "RMS variance 8.2 dB" unless the user asked for technical detail.

1. State limitations. Mention if pitch tracking was basic/fallback, if the

audio was noisy, if no transcript was supplied, or if word-level alignment was unavailable.

Pattern Review Workbench

When the request involves approving, rejecting, renaming, or building a pattern library:

1. Open report.html.
2. Use Pattern Lens cards or the Pattern Candidates table to choose a

candidate.

1. In Pattern Review Workbench, listen to the span, set the decision

(Approve, Needs review, or Reject), edit the analyst label/pattern ID, and add notes.

1. Copy or download the JSON payload.
2. If approved, apply it with the included suggested_cli command or rerun the

analyzer with --pattern-library, --save-pattern-label, and --save-pattern-rank.

The HTML is static and does not write to disk by itself. The exported payload is the handoff object an agent can use to update pattern-library.json without guessing which candidate the analyst meant.

Visual-Only Sharing

When the user wants fewer words or a shareable visual:

1. Open report.html.
2. Click Visual only to hide summaries, tables, limitations, and review text.
3. Choose the visual layout: Map for analysis, Card for a shareable image,

or Library for pattern comparison.

1. If a transcript is supplied, expect sparse words to appear as dot-on-arc,

connector-line, translucent-card callouts above the inflection arcs. These are approximate visual anchors, not word-level forced alignment.

1. Click Download image to export the active visual snapshot as a PNG.

The PNG export is generated locally from the report's embedded SVG; it does not upload audio or call an external screenshot service.

Visual snapshots use a smoothed, downsampled pitch presentation contour so a stakeholder can read the delivery shape without raw frame-level pitch jitter. The analyzer still keeps raw pitch/time-series data for metrics, JSON, and technical review.

Report Shape

Use this structure when replying:

## Prosody Readout
- Overall pattern:
- Strongest delivery signal:
- Pacing and pauses:
- Pitch and vocal variety:
- Emphasis:
- Visualization:
- Limitations:

## Practical Notes
1. ...
2. ...
3. ...

For chat surfaces, default to summarizing report.md. Before attaching or linking report.html outside the local machine, state whether it embeds raw voice audio and confirm that sharing the audio is approved. Use --share-safe when the user wants a report that omits the audio player and raw audio copy.

Interpretation Rules

• Treat pitch, intensity, and pause metrics as evidence, not verdicts.
• Treat pattern labels as descriptive contour sketches, not phonological or

accent diagnoses.

• If the user or analyst supplies a known pattern label, preserve that label as

analyst input and do not "correct" it from fallback metrics alone.

• If the user asks the agent to discover patterns, surface candidates and

families with confidence language: "candidate", "possible", "listen here", "similar contour family".

• Do not infer emotion, honesty, confidence, pathology, or personality from

prosody alone.

• If the user wants coaching, frame suggestions as experiments:

"try a shorter pause before the second sentence" rather than "you sound wrong."

• If comparing two takes, normalize around the user's stated goal. A "better"

take depends on purpose: warmth, clarity, authority, story tension, speed, or calm.

• If the audio contains multiple speakers, warn that the bundled analyzer is

single-speaker oriented and needs diarization before strong conclusions.

Visualization Guidance

Read references/interface-design.md before creating, editing, or reviewing HTML artifacts. The report should feel like a polished listening instrument, not a generic data dump. The bundled report.html generator is the reference implementation for palette, spacing, controls, and responsive behavior. Read references/pattern-analysis.md when the request is about identifying, matching, or visualizing prosodic patterns. Read references/pattern-library.md when the request is about building a reusable pattern library, saving approved exemplars, or matching future clips to known examples.

Prefer an interactive HTML report for v1:

• audio player
• active-audio focus that trims long quiet leading/trailing edges from the

analysis/playback copy while preserving the original input, including clips where speech occupies only a small fraction of the selected file

• waveform
• energy/loudness contour
• pitch contour
• pause bands
• summary cards
• delivery summary
• warm approachable visual theme with clear hierarchy, generous hit targets,

tabular numbers, balanced headings, and tactile control states

• visual snapshot SVG built from the real waveform, pitch, loudness, pause, and

top-pattern data

• smoothed presentation pitch contours in visual snapshots, while preserving raw

pitch data for metrics and technical traces

• visual layout selector with Map, Card, and Library views
• sparse transcript word callouts above inflection arcs when --transcript is

supplied: dot on contour, connector line, and readable translucent word card

• collision-aware word-card placement that separates dense labels or skips a

label when no clean slot is available

• Visual only toggle that hides word-heavy sections for stakeholder review
• Download image button that exports the active visual snapshot PNG
• top "listen first" moments
• progression snapshot across opening/middle/closing thirds
• pattern lens with normalized contour mini-maps for candidate prosodic shapes
• pattern library status, saved exemplar notes, and nearest approved-example

matches when --pattern-library is supplied

• Pattern Review Workbench for selecting, approving/rejecting, renaming,

annotating, and exporting candidate review JSON

• pattern candidate table with family IDs and click-to-seek controls
• click-to-seek on waveform, energy, and pitch charts
• synchronized playhead across charts
• scrubber, playback speed, previous/next moment, active-moment looping,

custom loop duration, and set-loop-from-playhead control

• pause/peak visibility toggles
• review candidate buttons, decision segmented control, label/ID fields, notes,

copy JSON, and download JSON controls

• visual-only and image-download controls in the main toolbar
• active visual layout controls near the visual snapshot

Static PNG is useful for sharing, but less useful for inspection. Animation is a later enhancement only if it clarifies timing; do not build animation for theater.

Progression Over Time

For repeated speech analysis, label each run with --speaker, --goal, --memo-type, and --take-label, and append compact trend records with --history.

Stable trend metrics for v0.5:

• pause ratio
• pause count per minute
• long pause count per minute
• rough pitch variability in semitones
• rough pitch IQR in semitones
• pitch coverage ratio
• intensity standard deviation
• possible acoustic peaks per minute
• speaking rate WPM only when transcript/alignment exists

Compare only like with like. A calm instructional memo should not be judged against a hype/storytelling take without noting the goal mismatch.

Toolchain Reference

Read references/toolchain.md when:

• the user asks how the analysis works
• the fallback analyzer is not enough
• you need word-level alignment, phoneme-level timing, emotion feature sets, or

publication-quality visualizations

• the user asks for Praat/Parselmouth or DTW matching

Read references/pattern-analysis.md when:

• the user asks for speech/accent pattern discovery
• a known prosodic pattern exemplar is supplied
• you need to explain the difference between waveform, pitch contour, intensity

contour, rhythm, and pattern families Read references/pattern-library.md when:

• the user wants to build a reusable pattern library
• an analyst accepts/rejects/renames a candidate pattern
• future clips should be matched to approved exemplars

High-fidelity path:

• Praat/Parselmouth for pitch, intensity, duration, spectrogram, jitter/shimmer
• DTW matching for variable-speed contour similarity against approved examples
• WhisperX or Montreal Forced Aligner for word/phoneme timing
• openSMILE for standardized acoustic feature sets
• librosa + Plotly for richer visual reports

Praat/Parselmouth is optional. The bundled script still runs with only Python, numpy, ffmpeg, and ffprobe; --pitch-method auto uses Praat when installed and falls back otherwise.

Output Scorecard

Read references/output-scorecard.md before reviewing publish-quality outputs. Minimum acceptable report quality is 14/15, with these mandatory:

• analyzer ran on the actual audio
• JSON, Markdown, and HTML artifacts exist
• pattern requests include pattern_analysis in prosody.json
• pattern-library or review requests include a usable Pattern Review Workbench

in report.html

• visual-sharing requests include working Visual only and Download image

controls, plus Map, Card, and Library visual layouts

• transcript-backed visual requests include sparse word callouts on visual arcs
• long dead-air heads/tails are auto-focused and disclosed in active_audio
• limitations are stated
• no claims are made about medical conditions, honesty, personality, emotion, or

intent

Verification

Before claiming a run is complete:

python3 /scripts/prosody_analyze.py --help
python3 /scripts/prosody_analyze.py /absolute/path/to/test-audio.ogg \
  --out-dir /tmp/prosody-lens-smoke
test -f /tmp/prosody-lens-smoke/report.html
test -f /tmp/prosody-lens-smoke/prosody.json

For HTML/UI changes, open report.html and verify:

• audio playback advances without stalls
• seek buttons and chart click-to-seek work
• loop duration and set-loop-from-playhead work
• pause/peak toggles work
• Pattern Review Workbench selects candidates, switches decision state,

generates valid JSON with signature, sequence, and suggested_cli, and copy/download controls are wired

• Visual only hides word-hea

…

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: jeremyknows
• Source: jeremyknows/prosody-lens
• License: MIT

Install and usage instructions live in the source repository linked above.