You ask an AI for advice, get a confident-looking answer, and wonder whether it missed something. Checking by hand means opening another app, pasting the same question, and comparing two long replies. The chore is small, but easy to skip when you are in the middle of something else.
Poly Duo is meant to shorten that check. It sends one question to ChatGPT and Claude, then presents a comparison of the answers. The point is not to have one model rewrite or endorse the other. It is to make agreement and disagreement easier to see, so you can decide what deserves a closer look.
From one prompt to three blocks
The described flow starts with a question. ChatGPT answers, then Claude answers independently, without seeing ChatGPT's response. Poly Duo compares the two and returns three sections: what they agree on, where they differ, and what you should verify yourself. The developer says the comparison takes about a minute.
That is a useful distinction from simply asking one model to critique another's answer. If the second model sees the first response, it may be influenced by its framing. Here, the answers are produced separately before the comparison. The underlying models still produce the content, though. Poly Duo's job is to organize the contrast, not to establish which answer is true.
The product is built around apps people already use, rather than asking them to move a question into a separate multi-model chat service. The developer says the prompt goes directly to the user's ChatGPT and Claude apps, with no Poly server in between. That is a description of the design, not a guarantee that every privacy concern is settled: the two services still receive the question, and their own account and data practices apply.
A phone shortcut, not a new AI model
On iPhone, the developer describes Poly Duo as a shortcut built on the official actions in the ChatGPT and Claude apps. It requires iOS 18 or later and can be triggered through the Action Button, Siri, or Back Tap. Free accounts are said to be enough. In practical terms, it is a way to coordinate two existing apps, not a model of its own or a replacement for either one.
The product is listed for iOS and Android, but the implementations are not described as identical. The iPhone flow is the shortcut. For Android, the developer points to a separate Poly app on Google Play. Readers looking for the same exact setup on both platforms should not assume that the Android experience uses the same mechanism.
Poly Duo is free. Its appeal depends on already wanting to use both ChatGPT and Claude, and being comfortable sending the same prompt to each. If you only use one of them, the comparison adds another app and another answer to review rather than removing work.
What a disagreement can and cannot tell you
The three-part summary gives a sensible place to focus: differences may reveal assumptions, missing context, or details that merit verification. But disagreement is not automatically a warning, and agreement is not proof. Two systems can share a blind spot, repeat a common error, or produce answers that sound compatible while relying on weak information. The described output does not itself supply citations or independently verify claims.
That makes the product more useful for orienting a human review than for signing one off. It can help surface a point you might otherwise overlook, especially when a question is open-ended. It is a weaker fit when the task needs a sourced answer, precise factual validation, or a decision where an error carries serious consequences. Those still call for checking reliable primary sources or getting appropriate expert advice.
The underlying problem is familiar: comparing two AI answers manually takes just enough effort that people may not do it. Poly Duo turns that comparison into a repeatable phone action, while leaving the important judgment with the user. It is for people who already use ChatGPT and Claude and want a quick second opinion on everyday questions. It is not for anyone who needs an automated fact-checker, a guarantee that an answer is correct, or a replacement for careful verification.
First time: your ChatGPT + Claude apps together on iPhone, free