GPT‑5.5 leak surfaces

A rumored GPT‑5.5 model briefly appeared in OpenAI’s Codex tooling this week, and the sighting set off a fresh round of release speculation. (piunikaweb.com) PiunikaWeb reported on April 22 that some Codex Pro users briefly saw a model picker listing “GPT-5.5,” “oai-2.1,” “arcanine,” and several “glacier-alpha” variants before the options disappeared. GitHub added model selection for Codex agents on github.com on April 14, creating a visible place where unreleased names could surface if internal labels slipped through. (piunikaweb.com, github.blog) Codex is OpenAI’s coding agent, the system that writes, edits, and tests software inside ChatGPT and developer workflows. OpenAI’s current product pages say Codex is powered by its frontier coding models, and OpenAI’s most recent confirmed release into Codex was GPT‑5.4 on March 5, 2026. (chatgpt.com, openai.com) That makes the leak notable for a simple reason: OpenAI has not announced GPT‑5.5 on its website, developer docs, or product blog as of April 23. OpenAI’s public model pages currently list GPT‑5, GPT‑5.1, GPT‑5.2, and GPT‑5.4, but not a 5.5 release. (openai.com, openai.com, openai.com) The names in the leak also fit how AI companies often handle model launches: internal codenames and checkpoint labels appear before polished product branding. The Information’s AI Agenda newsletter referred on March 25 to OpenAI’s new “Spud” model, giving independent support to the idea that a new OpenAI system exists even if its final public name is still unclear. (theinformation.com) Reports circulating around the leak say pre-training for the “Spud” model finished on March 24, 2026, but that detail has not been confirmed by OpenAI in a public post. Several secondary reports repeat the March 24 date, yet the strongest public corroboration available without an OpenAI statement remains The Information’s reference to a new “Spud” model rather than a full technical timeline. (pasqualepillitteri.it, tokenmix.ai, theinformation.com) The timing also fed launch chatter because OpenAI has been shipping model updates quickly this year. After GPT‑5.1 arrived in November 2025, OpenAI released GPT‑5.4 on March 5, 2026 with a 1 million-token context window and native computer-use features for agents in Codex and the application programming interface. (openai.com, openai.com) Speculation jumped further when traders on Polymarket priced a high probability of a GPT‑5.5 release on April 23, but prediction markets measure bets, not confirmation. As of Thursday, the only firm public facts are the Codex sighting, the leaked names, and OpenAI’s silence on an official GPT‑5.5 launch. (polymarket.com, piunikaweb.com, openai.com) If OpenAI does unveil a new model, the cleanest signal will be an announcement on its own site or in its API and ChatGPT release notes. Until then, GPT‑5.5 is still a leak, not a launch. (openai.com, openai.com)