{"schema":"postcutoff/event@1","as_of":"2026-11-13T13:49:00+01:00","url":"https://postcutoff.com/e/2025-08-07-gpt-5/","md":"https://postcutoff.com/e/2025-08-07-gpt-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":"2025-08-07-gpt-5","date":"2025-08-07","date_precision":"day","short_title":"OpenAI launches GPT-5","deck":null,"takeaway":"GPT-5 unified OpenAI's fast and reasoning models into one system with a real-time router, becoming the default ChatGPT model for all users with state-of-the-art results in coding, math and health, and reduced hallucinations.","category":"model-release","category_label":"Model releases","importance":5,"confidence":"high","status":{"key":"confirmed","labels":["Confirmed"]},"sources":[{"n":1,"title":"Introducing GPT-5 (OpenAI)","url":"https://openai.com/index/introducing-gpt-5/","type":"official","group":"primary","domain":"openai.com"},{"n":2,"title":"GPT-5 System Card (OpenAI)","url":"https://openai.com/index/gpt-5-system-card/","type":"docs","group":"primary","domain":"openai.com"}],"official":2,"filed":"2026-09-29","updated":"2026-09-29","orgs":["OpenAI"],"title":"OpenAI launches GPT-5","summary":"GPT-5 unified OpenAI's fast and reasoning models into one system with a real-time router, becoming the default ChatGPT model for all users with state-of-the-art results in coding, math and health, and reduced hallucinations.","key_facts":["Released 7 August 2025 to all ChatGPT users, including free tier","SWE-bench Verified: 74.9%, per OpenAI","AIME 2025 (no tools): 94.6%, per OpenAI","Unified system: fast model + GPT-5 thinking + router","API family: gpt-5, gpt-5-mini, gpt-5-nano; followed by GPT-5.1 (November) and GPT-5.2 (December 2025)"],"key_numbers":[],"tags":["llm","reasoning","gpt","frontier"],"science":null,"body_md":"## What happened\n\nAfter over two years of anticipation, OpenAI shipped GPT-5; reception mixed praise for capability with complaints over the removal of older models, which were partly restored.\n\n## Why it matters\n\nBrought reasoning-model capability to hundreds of millions of free users by default.","disputed":[],"related":[{"id":"2025-12-11-gpt-5-2","url":"https://postcutoff.com/e/2025-12-11-gpt-5-2/","date":"2025-12-11","date_precision":"day","short_title":"OpenAI releases GPT-5.2","deck":null,"takeaway":"Illustrated the compressed release cadence of late 2025, with frontier leadership changing hands within weeks.","category":"model-release","category_label":"Model releases","importance":3,"confidence":"medium","status":{"key":"partly","labels":["Partly confirmed"]},"sources":2,"official":2,"filed":"2026-09-29","updated":"2026-09-29","orgs":["OpenAI"]},{"id":"2024-12-20-openai-o3","url":"https://postcutoff.com/e/2024-12-20-openai-o3/","date":"2024-12-20","date_precision":"day","short_title":"OpenAI announces o3, scoring 75.7–87.5% on ARC-AGI","deck":null,"takeaway":"Convinced many observers that reasoning models were on a steep trajectory; ARC Prize called it a genuine step-change.","category":"benchmark","category_label":"Benchmarks","importance":5,"confidence":"high","status":{"key":"confirmed","labels":["Confirmed"]},"sources":2,"official":2,"filed":"2026-09-29","updated":"2026-09-29","orgs":["OpenAI","ARC Prize"]},{"id":"2023-03-14-gpt-4","url":"https://postcutoff.com/e/2023-03-14-gpt-4/","date":"2023-03-14","date_precision":"day","short_title":"OpenAI releases GPT-4","deck":null,"takeaway":"Defined the frontier for over a year and triggered serious policy attention to AI risk (pause letter, hearings, summits).","category":"model-release","category_label":"Model releases","importance":5,"confidence":"high","status":{"key":"confirmed","labels":["Confirmed"]},"sources":2,"official":2,"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":null,"in_training_data":true},{"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"}