Analyze Accent Report

Turn a Coval accent testing report into a practical agent-fix plan. This skill assumes the user already ran comparable Coval evaluations across speaker accents, usually by creating one persona per accent voice and setting the report to Compare by Persona.

If no report or run results exist yet, ask for them. Do not invent results. If an end-to-end accent workflow skill is installed in the user's environment, use that workflow first to create the personas, runs, and report (see run-accent-testing), then return to this skill for analysis.

Inputs

Accept any of:

• Coval report URL or shared report URL
• report export, screenshots, or copied metric table
• Coval run IDs from the same accent testing sweep
• representative simulation links, recordings, transcripts, traces, or Human Review labels

If Coval CLI/API access is available, use it to inspect runs, simulations, metrics, transcripts, recordings, and traces. If access is not available, work from the provided report/export and ask only for the smallest missing evidence needed to avoid guessing.

Workflow

1. Verify The Comparison

Confirm:

• same agent or intentional agent variant
• same test set and sampled cases across accent personas
• same metrics across runs
• all compared runs reached terminal status
• the report is grouped by accent persona, with Standard Customer (or another clear neutral baseline) as the comparison point
• each accent persona differs from the baseline only by its accent voice (same behavior prompt and language); if not, the comparison mixes accent with behavior and you must say so

Call out caveats before interpreting results. Common caveats: missing accents, different test cases, incomplete runs, too few simulations per accent (likely on this suite, because accent voices are lower-concurrency), changed agent config between runs, or accent personas whose prompts diverge from the baseline.

2. Build Per-Accent Deltas

Compare each accent against the baseline. Lead with speech recognition, since accent testing is primarily a recognition stress test. Track direction and magnitude for:

Area	Typical Signals
Speech recognition (headline)	Transcription Error (audio-derived, always available) is the default; use STT WER from traces only after confirming it actually scored — it silently fails when the agent emits no STT spans
Task outcome	composite score, task completion, scenario-specific pass/fail metrics
Responsiveness	latency, time to first audio, trace TTFB, provider response time
Conversation flow	repeated confirmation/clarification loops, repetition, sentiment, turn timing
Call shape	turn count, audio duration, early termination, abnormally short or long calls
Scoreability	UNKNOWN, missing, failed, or unscored metric results

Use the metric's natural direction. Lower is better for WER, transcription error, latency, silence, and confirmation-loop counts. Higher is better for success, completion, and accuracy metrics.

Do not overfit to one row. Treat one-off failures as hypotheses unless the metric, transcript, recording, or trace evidence supports the pattern.

Treat UNKNOWN, missing, failed, or unscored metric results as evidence to inspect, not as data to ignore. Under heavy accent stress, a judge may be unable to score because the call ended early, the transcript is too sparse, or the interaction became too anomalous to evaluate.

One specific gap to recognize, not misread: STT Word Error Rate that is FAILED/empty on nearly every simulation is a tracing gap, not an accent signal. That metric only computes when the agent's traces carry STT spans with a recognized hypothesis and a reference; many voice stacks (Vapi/PSTN especially) emit no such spans, so it fails uniformly across all personas including the baseline. When that happens, lead recognition with Transcription Error (audio-derived, needs no traces) and recommend instrumenting STT spans as a trace-setup fix — do not report the empty STT WER column as if accents scored poorly on it.

3. Inspect Representative Evidence

Open or request representative simulations:

• worst regression for each affected accent
• one healthy baseline simulation
• any surprising metric outlier
• any UNKNOWN, missing, failed, or unscored metric result
• very short calls, very long calls, or early terminations compared with baseline
• cases where binary task metrics passed but the transcript or recording shows the agent mis-heard names, numbers, addresses, or other key entities
• Human Review disagreements, if present

For each important example, inspect the transcript and recording when available. Look specifically for mis-recognized words, wrong entities captured, and extra confirmation loops the baseline did not need. Use traces when present to distinguish STT errors from downstream reasoning or tool errors. Separate metric evidence from listening judgment and label anything that is inferred.

4. Diagnose By Accent

Use accent hypotheses, then verify them against evidence:

Accent	Likely Failure Modes To Check
Standard Customer	General agent, test, metric, or tool issue if this baseline also fails
Indian Accent (Vidya)	Phoneme/vowel recognition, fast or stressed-syllable speech, mis-captured names and numbers
German Accent (Marshal)	Consonant devoicing (final /d/→/t/), vowel shifts, formal phrasing, STT word errors on common terms
Chinese Accent (Ziyu)	Tone and final-consonant recognition, mis-heard digits and entities, over-confirmation
US Southern Accent (Cletus)	Vowel shifts and drawl, contractions, regional phrasing, STT word errors
Nigerian Accent (Kehinde)	Rhythm and stress patterns, vocabulary, mis-captured entities, confirmation loops
Malaysian Accent (Darryl)	Syllable-timed rhythm, dropped final consonants, mis-captured entities, confirmation loops

The shared pattern across accents is the same: check whether the STT layer mis-transcribes accented speech, whether mis-transcription propagates into wrong task outcomes, and whether the agent recovers with read-back or clarification. If the report uses different persona labels, map each one to the closest accent and state the mapping.

5. Recommend Fixes

Recommend specific next steps. Prefer small, testable changes over generic advice. Separate:

• Agent prompt changes: read-back of critical entities (names, numbers, addresses), explicit clarification strategy, concise confirmation, and escalating uncertainty when recognition confidence is low.
• STT/recognition adjustments: STT model/config (e.g. an accent- or multilingual-robust model), VAD thresholds, partial/final transcript handling, endpointing, or per-language/locale routing.
• Tool handling fixes: validate entities captured from speech before acting, idempotency, retry policy, and grounding tool results in confirmed values.
• Trace or metric setup: add OpenTelemetry traces, STT/trace metrics, or Human Review labels when the current evidence cannot explain the failure.
• Coverage changes: add more cases or accents only when the current data shows a blind spot or the sample size is too thin.

Tie each recommendation to the accent, metric delta, call-shape change, scoreability issue, and representative simulation evidence that motivated it. If a recommendation cannot be tied to evidence, mark it as a hypothesis and explain how to validate it.

6. Plan The Confirmation Run

End with a small validation plan:

• which fix to try first
• which accent(s) and test cases to rerun
• which metrics should improve (usually STT WER / transcription error and task outcome for the affected accent)
• what regression guard should stay unchanged (the baseline should not get worse)

Use the same baseline/report structure so the user can compare before and after.

Output Format

Return:

## Accent Report Analysis

### Executive Summary
- Biggest accent regression:
- Most important call-shape or scoreability anomaly:
- Most likely root cause:
- Highest-confidence next fix:

### Scope And Caveats
- Report/runs analyzed:
- Baseline:
- Missing or weak evidence (note thin per-accent samples from low concurrency):

### Per-Accent Regression Table
| Accent | Main Regression Or Anomaly | Evidence | Likely Cause | Confidence |
|--------|----------------------------|----------|--------------|------------|

### Representative Evidence
- Baseline simulation:
- Regression examples:
- UNKNOWN/unscored examples:
- Trace/Human Review evidence:

### Recommended Agent Fixes
1. Fix:
   - Why:
   - Exact change:
   - Validation:

### Confirmation Plan
- Rerun:
- Metrics to watch:
- Pass criteria:

Keep the final answer concise enough for a product or engineering owner to act on. Include links or IDs for report, run, simulation, trace, and Human Review evidence when available.

Guardrails

• Do not expose API keys, secrets, or private customer data.
• Do not claim traces explain a result unless trace data was available and inspected.
• Do not ignore UNKNOWN, missing, failed, or unscored metrics. Explain whether they look like measurement gaps or symptoms of an anomalous conversation.
• Do not confuse accent comprehension (an STT/recognition problem) with generated voice quality (a TTS problem). This suite tests whether the agent understands accented callers, not how the agent's own voice sounds.
• Do not recommend changing Coval metrics or tests when the evidence points to the user's agent, unless the metric/test setup is genuinely flawed.
• Do not present "expand accent coverage" as the main recommendation when the report already shows a clear fixable failure on an existing accent.
• Do not over-read thin samples. Accent voices are lower-concurrency, so each accent run may have few simulations — flag small-sample conclusions as tentative.