GPT-Live-1 first impressions: most natural voice model yet, but instruction following is unreliable

kolchinski · reddit · 2026-09-13

ThunderPhone, an AI phone-agent company, tested OpenAI's GPT-Live-1 over two days with a 13,000-token insurance qualification script, a dozen real test calls and 25 simulated ones.

The good: the most natural-sounding model they've put on a phone line. Full-duplex turn-taking, interruptions and backchannels work out of the box; first audio arrives 1.3s after the caller stops, with zero VAD or turn-taking logic on their side.

The bad: instruction following is unreliable.

Alphanumerics are risky: a 14-character claim number gained a phantom "Y" in audio; "Q" became "X" in Russian; digit dates came back as "fifty-five ninety-five."

Accents: fluent Russian and Luganda but with thick American accents; the first Luganda call got answered in Swahili. Full transcripts and audio clips on the author's blog.

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