Introduction

Signal answers one question for someone who owns a voice agent in production: what should I fix, and did my fix work? You connect a Retell agent. Signal reads its calls, finds the problems that repeat across them, and orders them by how much they hurt your callers. After you ship a change, it shows what production did before and after, so you can see whether the change helped or the numbers only moved. Signal is for the product manager, QA lead or AI engineer who runs a Retell voice agent and can edit its prompts, flow and tools. Retell is the only platform Signal supports at launch.

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What you get

Connect an agent, approve a short brief of what it is for, and Signal imports your latest calls (up to 500 from the last 30 days). From then on it keeps up with new calls on its own. You get:

• Issues with a place, a cause and a change. Not “dead air”, but “a lookup at one step takes nine seconds”, with a suggested fix and quotes from the calls behind it. Confirmed defects sit in Fix, and changes you control that move your numbers sit in Improve. When the calls do not show why something happens, Signal says Cause not established and does not guess. See Issues.
• Version comparisons. When you publish a change in Retell, Signal shows what changed and what production did afterwards, and tells you when a difference is real and when there are not enough calls yet. See Versions.
• Tests from real calls. A call behind an issue can become a test: a simulated caller with the original caller’s goal, run against a version of your agent. Testing is opt-in and needs a separate Retell key that can write, plus a monthly budget you set. See Test a fix.

New workspaces open on a read-only demo agent built from synthetic calls, so you can look around before you connect anything.

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How it differs from reading transcripts

A transcript shows you one call. Signal reads every call and groups what it finds by the change that would fix it, so three symptoms of one slow tool become one row. It makes its own reading of each call and does not rely on Retell’s summary, sentiment or success flag. See How Signal works.

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Limits to know about

• New calls show up within about 15 minutes. If you paste Signal’s webhook URL into the agent in Retell, each call arrives as soon as it ends. Analysis takes a few minutes more. See Connect Retell.
• Confirmed patterns only. Fix and Improve list problems Signal has confirmed across several calls, with a cause it established. A confirmed pattern without an established cause is listed apart, under Cause not established. Anything not yet confirmed is kept and appears once it is.
• English works best. Signal reads calls in other languages, but its analysis is tuned for English.

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Where to go next