How do I test a Retell AI agent?

Point TestMu AI at your Retell AI agent, ingest your intake scripts and knowledge or connect a source, and let it auto-generate scenarios. It then places simulated phone conversations and live or recorded calls into the agent, scoring each booking, verification, or transfer on quality and telephony metrics with a clear pass or fail. Explore agent testing to see the full workflow.

Why should I test agents built on Retell AI?

Retell AI makes it fast to ship a voice agent that answers and places real phone calls, but that agent verifies insurance, books appointments, and quotes your policies to every caller. A single prompt, knowledge, or call-flow change can silently break a booking journey that worked yesterday. Independent testing catches a hallucinated price, a missed reschedule, a failed function call, or a slow turn before a real caller hears it.

What can TestMu AI test in a Retell AI agent?

Whether the agent answers correctly across thousands of call scenarios, fires the right function call to book or look up a record, holds its guardrails against hallucinated policies, remembers context across a multi-turn call, and transfers to a human at the right moment. It also measures response latency, speech-to-text accuracy, interruption and turn-taking handling, and 30+ telephony metrics for the call itself.

What are the 9 quality metrics?

Every call is scored on nine metrics: bias detection, hallucination detection, completeness, context awareness, response quality, conversation flow, user satisfaction (CSAT), file handling quality, and file generation accuracy, each with customizable 0-100% pass/fail thresholds. The same approach powers TestMu AI's voice agent testing across every channel.

Can I test Retell AI voice agents for latency, interruptions, and speech quality?

Yes. Latency and turn-taking are where Retell AI agents most often feel robotic, so TestMu AI runs spoken calls end to end and measures response latency, speech-to-text accuracy, an average pitch tracker, a Voice Quality Index, and how the agent handles interruptions and barge-in, judging it on how it sounds to a caller, not just on a transcript.

Can I run Retell AI agent tests in CI/CD?

Yes. Run your call-scenario suite on demand or wire it into CI with scheduling, so every prompt, knowledge, voice, or call-flow change you push in Retell AI is tested automatically. Gate releases on the result to block any change that regresses a known-good booking or verification flow.

How does the Go-Live assessment work?

Each run produces a verdict: Green (80 or above) is ready for production, Yellow (65-79) is ready with caveats, and Red (below 65) is not ready. The score combines four equally weighted dimensions, namely functional completeness, quality standards, risk profile, and operational readiness, paired with a confidence level scaled to how many calls you have evaluated.

Does this replace Retell AI's own QA tooling?

No, it complements it. Retell AI gives you call logs, latency breakdowns, and its own QA inside the builder; TestMu AI is an independent layer that evaluates the agent from the outside, the way a caller would, across thousands of scenarios at once. Keep building in Retell AI and use agent testing to prove the agent behaves correctly before and after every release.

Test the Voice Agents You Build on Retell AI

Test the voice agents you build on Retell AI. TestMu AI calls them like real customers, scoring every conversation on 9 quality metrics and every call on 30+ telephony metrics with a clear go-live verdict.

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Test Every Retell AI Call. One Platform.

Conversation Quality

Inbound Calls

Outbound Calls

Test What Your Retell AI Agent Says

Simulate thousands of real phone conversations against your Retell AI agent and score every turn on 9 quality metrics, even when a caller goes off-script.

9 Quality Metrics

Catch the failure that matters: an AI receptionist inventing an opening hour or a policy it cannot back up. Score bias, hallucination, completeness, context awareness, and conversation flow on every turn.

Scenarios From Your Own Knowledge

Ingest your intake scripts, insurance rules, and FAQ PDFs or connect Confluence, Jira, and GitHub, then auto-generate the reschedule, cancellation, and pricing edge cases your Retell AI agent will hit.

Go-Live Assessment

Get a Green, Yellow, or Red production-readiness verdict with customizable 0-100% pass/fail thresholds before the agent picks up a live caller.

From the First Ring to Production

Pre- and Post-Launch, End to End

Place simulated test calls into your Retell AI agent before launch, then batch-analyze the real production recordings it logs with the same metrics, so an appointment setter that passed in staging holds the same bar when call volume spikes.

Full Coverage for Retell AI Voice Agents

Score what the agent says across 9 quality metrics, and how it sounds across 30+ flow, latency, audio, and speech-to-text metrics, so a hallucinated quote and a half-second delay both get caught.

Call-Center Ops Metrics

Track the numbers a Retell AI deployment lives by: CSAT and detected sentiment, containment rate, early hang-up rate, and how often the agent transfers a caller to a human.

Go-Live Assessment by Confidence

Get a Green, Yellow, or Red verdict from four weighted dimensions, with confidence scaled to how many calls you have evaluated, so you launch on evidence rather than a single good demo call.

Inside Retell AI Voice Testing on TestMu AI

9 QUALITY METRICS

Score Conversations on 9 Quality Metrics

Run your Retell AI agent across thousands of call scenarios, from a clean booking to a caller who changes the date twice, scoring the same nine metrics every turn with customizable 0-100% pass/fail thresholds.

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Bias, hallucination, and completeness checks
Context awareness and conversation flow
CSAT, file handling, and generation accuracy

PRE & POST EVALUATION

Test Before Launch, Analyze After

Pre-launch, TestMu AI dials live calls into the agent; post-launch, it batch-analyzes the real recordings Retell AI logs, so an agent that passed in staging holds the same bar once it is taking traffic.

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Live inbound and outbound test calls
Passive monitoring and outbound number pool
Batch analysis of production call recordings

SCENARIO & VOICE CONFIGURATION

Configure Scenarios and Voices

Shape each test call to mirror a real one: generate scenarios from your own intake scripts and knowledge, pick a caller voice and accent, add the background noise of a car or busy office, and control call flow down to response timing.

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Auto-generated scenarios and a persona library
15 background-noise presets for resilience
Masked numbers and call-flow controls

AUDIO, STT & ISSUE DETECTION

Catch Failures Automatically

Beyond pass and fail, the platform surfaces why a call broke, from a hallucinated policy or fumbled interruption to patchy audio or a misheard name, with precise mismatch logging you can take back into Retell AI.

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Pitch tracker, Voice Quality Index, and SNR
Speech-to-text accuracy mapping
Automated issue tags for every failure

Built on Universal Testing Foundations

Project & Environment Management

Test Profiles & Personas

Inject reusable caller data and use a pre-built or custom persona library for the patient, lead, or repeat-caller scenarios your agent handles.

Validation Criteria

Define custom, evidence-based pass/fail rules per call scenario with High/Medium/Low confidence tracking.

Security & Infrastructure

Execute via HyperExecute with optional secure tunnels for firewall-restricted voice and telephony stacks.

Scheduling Engine

Automate call-test runs with preset frequencies or full custom cron expressions and IANA timezone support.

Go-Live Assessment

Get a Green, Yellow, or Red verdict from four weighted dimensions with AI-powered failure-pattern analysis.

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TestMu AI (Formerly LambdaTest)/Retell AI Testing

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Test the Voice Agents You Build on Retell AI

Test Every Retell AI Call. One Platform.

Test What Your Retell AI Agent Says

Test Retell AI Inbound Phone Agents

Test Retell AI Outbound Phone Agents

From the First Ring to Production

Pre- and Post-Launch, End to End

Full Coverage for Retell AI Voice Agents

Call-Center Ops Metrics

Go-Live Assessment by Confidence

Inside Retell AI Voice Testing on TestMu AI

Score Conversations on 9 Quality Metrics

Test Before Launch, Analyze After

Configure Scenarios and Voices

Catch Failures Automatically

Built on Universal Testing Foundations

Success Stories of TestMu AI (Formerly LambdaTest)

Some Love from our Customers

Frequently asked questions