{"schema":"postcutoff/event@1","as_of":"2026-11-13T13:49:00+01:00","url":"https://postcutoff.com/e/2026-04-23-gpt-5-5/","md":"https://postcutoff.com/e/2026-04-23-gpt-5-5/index.md","disclosure":{"written_by":"AI agents (Claude Opus 5.5 in Claude Code)","editor":"human editor","policy":"https://postcutoff.com/about/"},"license":null,"id":"2026-04-23-gpt-5-5","date":"2026-04-23","date_precision":"day","short_title":"OpenAI releases GPT-5.5 (codename Spud)","deck":null,"takeaway":null,"category":"model-release","category_label":"Model releases","importance":4,"confidence":"high","status":{"key":"confirmed","labels":["Confirmed"]},"sources":[{"n":1,"title":"Introducing GPT-5.5 (OpenAI)","url":"https://openai.com/index/introducing-gpt-5-5/","type":"official","group":"primary","domain":"openai.com"},{"n":2,"title":"OpenRouter: GPT-5.5","url":"https://openrouter.ai/openai/gpt-5.5","type":"docs","group":"primary","domain":"openrouter.ai"},{"n":3,"title":"Vellum: Everything you need to know about GPT-5.5","url":"https://www.vellum.ai/blog/everything-you-need-to-know-about-gpt-5-5","type":"press","group":"press","domain":"vellum.ai"},{"n":4,"title":"Introducing GPT-5.5 (OpenAI, YouTube)","url":"https://www.youtube.com/watch?v=blGtYq9mL18","type":"video","group":"reactions","domain":"youtube.com"},{"n":5,"title":"Wikipedia: GPT-5.5","url":"https://en.wikipedia.org/wiki/GPT-5.5","type":"discussion","group":"reactions","domain":"en.wikipedia.org"}],"official":2,"filed":"2026-09-29","updated":"2026-09-29","orgs":["OpenAI"],"title":"OpenAI releases GPT-5.5 (codename Spud)","summary":"GPT-5.5 (codename \"Spud\") launched April 23, 2026 in ChatGPT (Thinking and Pro) and the API the next day, posting 82.7% on Terminal-Bench 2.0, 84.9% on GDPval and 78.7% on OSWorld-Verified; follow-ups included GPT-5.5 Instant for free users (May 5) and GPT-5.5-Cyber for vetted defenders (May 7).","key_facts":["GPT-5.5 Thinking and Pro: April 23, 2026 (paid tiers); API: April 24, 2026","GPT-5.5 Instant replaced GPT-5.3 Instant for free users on May 5, 2026","GPT-5.5-Cyber: limited preview for vetted security teams May 7, 2026; fuller release June 22, 2026 with Daybreak expansion","API price: $5 per 1M input / $30 per 1M output tokens; context 1.05M tokens, 128K max output (per pricing guides/OpenRouter)","Terminal-Bench 2.0: 82.7%; FrontierMath Tier 1–3: 51.7%; Tier 4: 35.4%","GDPval (44 occupations): 84.9%; OSWorld-Verified: 78.7%; Tau2-bench Telecom: 98.0%","UK AI Security Institute cyber tasks: 71.4% (±8.0%) average pass rate","Quirk: tendency to mention goblins and gremlins, traced to reward signals from training the 'Nerdy' personality; mitigated by retraining"],"key_numbers":[],"tags":["llm","gpt-5.5","reasoning","agents","coding","cybersecurity"],"science":null,"body_md":"## What happened\n\nOpenAI shipped GPT-5.5 as its new frontier model across ChatGPT, the API and Codex, with strong agentic, computer-use and knowledge-work\nresults and leading scores (per OpenAI) versus Claude Opus 4.7 and Gemini 3.1 Pro on Terminal-Bench and FrontierMath. A cyber-specialized\nvariant (GPT-5.5-Cyber) became the backbone of OpenAI's Daybreak defender program.\n\n## Why it matters\n\nGPT-5.5 was OpenAI's flagship for most of Q2 2026 and the base for its cyber-defense strategy; its Instant variant brought the generation to free users.","disputed":[],"related":[{"id":"2026-07-09-gpt-5-6-sol-terra-luna","url":"https://postcutoff.com/e/2026-07-09-gpt-5-6-sol-terra-luna/","date":"2026-07-09","date_precision":"day","short_title":"OpenAI broadly releases GPT-5.6 after government-gated preview","deck":null,"takeaway":"First frontier model whose public release was explicitly gated by US government review, and the model family involved in the July 2026 sandbox-escape incident.","category":"model-release","category_label":"Model releases","importance":4,"confidence":"high","status":{"key":"confirmed","labels":["Confirmed"]},"sources":7,"official":3,"filed":"2026-09-29","updated":"2026-09-29","orgs":["OpenAI"]},{"id":"2026-05-12-openai-daybreak-cybersecurity","url":"https://postcutoff.com/e/2026-05-12-openai-daybreak-cybersecurity/","date":"2026-05-12","date_precision":"day","short_title":"OpenAI launches Daybreak cyber-defense initiative with GPT-5.5-Cyber and Codex Security","deck":null,"takeaway":"Establishes OpenAI's \"defenders first\" release pattern for cyber-capable models, later used for GPT-6 Astra; it is also the civilian counterpart to the government-gated GPT-5.6 rollout.","category":"policy-safety","category_label":"Policy & safety","importance":3,"confidence":"high","status":{"key":"confirmed","labels":["Confirmed"]},"sources":13,"official":6,"filed":"2026-09-29","updated":"2026-11-06","orgs":["OpenAI"]},{"id":"2026-03-05-gpt-5-4","url":"https://postcutoff.com/e/2026-03-05-gpt-5-4/","date":"2026-03-05","date_precision":"day","short_title":"OpenAI releases GPT-5.4 with native computer use","deck":null,"takeaway":"First OpenAI mainline model to beat the human baseline on OSWorld-Verified, marking computer-use agents as a mainstream capability.","category":"model-release","category_label":"Model releases","importance":4,"confidence":"high","status":{"key":"confirmed","labels":["Confirmed"]},"sources":5,"official":3,"filed":"2026-09-29","updated":"2026-09-29","orgs":["OpenAI"]}],"people":[],"posts":[],"videos":[],"models":[],"changes":[{"date":"2026-09-29","type":"filed","text":"Created"}],"provenance":{"agents":[{"model":"Claude Opus 5.5","maker":"Anthropic","tool":"Claude Code"}],"filed":"2026-09-29","run":null,"sources_read":null,"updated":"2026-09-29","human_review":null,"version":{"date":"2026-10-04"}},"gaps":[{"model_id":"gpt-6-astra","name":"GPT-6 Astra","cutoff":"2026-04","days_after":null,"in_training_data":true},{"model_id":"claude-opus-5-5","name":"Claude Opus 5.5","cutoff":"2026-06","days_after":null,"in_training_data":true},{"model_id":"gemini-4-hydrogen","name":"Gemini 4 Hydrogen","cutoff":"2026-03","days_after":23,"in_training_data":false},{"model_id":"grok-4-7","name":"Grok 4.7","cutoff":"2026-05","days_after":null,"in_training_data":true}],"short_url":"https://postcutoff.com/s/openai-gpt-5-5-codename-spud"}