GPT-5.3

OpenAI · Mar 2026

The “less cringe” update: Instant tuned for tone, relevance and lower hallucinations, plus GPT-5.3-Codex for agentic coding. A personality patch shipped as a version number.

Sources

Official

• 2026-03-03 GPT-5.3 Instant — announcement.
• 2026-03 Introducing GPT-5.3-Codex — the coding sibling.
• 2026-03-03 9to5Mac: less cringe — press framing.

Writing & commentary

tk — to collect

Tweets

tk — fleet pass pending; mirror to archive

Official record

• Hallucination reductions of 26.8% (web) / 19.7% (internal knowledge) claimed vs prior models.
• tk — fill from primary sources

History

tk — context of the world at release; events and entanglements

Impressions

tk — day-of and longitudinal vibes to collect

← back to the Pantheon