{"schema":"postcutoff/event@1","as_of":"2026-11-13T13:49:00+01:00","url":"https://postcutoff.com/e/2025-05-22-claude-4/","md":"https://postcutoff.com/e/2025-05-22-claude-4/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":"2025-05-22-claude-4","date":"2025-05-22","date_precision":"day","short_title":"Anthropic releases Claude Opus 4 and Sonnet 4","deck":"Claude Code goes GA","takeaway":"Claude Opus 4 and Sonnet 4 led coding benchmarks and could work autonomously for hours; Opus 4 was the first model Anthropic deployed under its stricter ASL-3 safety standard, and Claude Code became generally available.","category":"model-release","category_label":"Model releases","importance":5,"confidence":"high","status":{"key":"confirmed","labels":["Confirmed"]},"sources":[{"n":1,"title":"Introducing Claude 4 (Anthropic)","url":"https://www.anthropic.com/news/claude-4","type":"official","group":"primary","domain":"anthropic.com"},{"n":2,"title":"Activating AI Safety Level 3 Protections (Anthropic)","url":"https://www.anthropic.com/news/activating-asl3-protections","type":"official","group":"primary","domain":"anthropic.com"},{"n":3,"title":"Claude Opus 4.1 (Anthropic)","url":"https://www.anthropic.com/news/claude-opus-4-1","type":"official","group":"primary","domain":"anthropic.com"}],"official":3,"filed":"2026-09-29","updated":"2026-09-29","orgs":["Anthropic"],"title":"Anthropic releases Claude Opus 4 and Sonnet 4; Claude Code goes GA","summary":"Claude Opus 4 and Sonnet 4 led coding benchmarks and could work autonomously for hours; Opus 4 was the first model Anthropic deployed under its stricter ASL-3 safety standard, and Claude Code became generally available.","key_facts":["Released 22 May 2025","SWE-bench Verified: Opus 4 72.5%, Sonnet 4 72.7%, per Anthropic","Opus 4 deployed with ASL-3 protections under the Responsible Scaling Policy","Claude Code generally available with VS Code and JetBrains integrations","Claude Opus 4.1 followed on 5 August 2025 (74.5% SWE-bench Verified)"],"key_numbers":[],"tags":["llm","claude","coding","agents","safety"],"science":null,"body_md":"## What happened\n\nAnthropic launched its fourth-generation models focused on long-running agentic coding tasks.\n\n## Why it matters\n\nCemented Claude's lead in coding agents and was the first frontier deployment under elevated safeguards for CBRN risk.","disputed":[],"related":[{"id":"2025-09-29-claude-sonnet-4-5","url":"https://postcutoff.com/e/2025-09-29-claude-sonnet-4-5/","date":"2025-09-29","date_precision":"day","short_title":"Anthropic releases Claude Sonnet 4.5","deck":null,"takeaway":"Pushed the length of tasks AI agents can reliably do and made agent-building infrastructure broadly available.","category":"model-release","category_label":"Model releases","importance":4,"confidence":"high","status":{"key":"confirmed","labels":["Confirmed"]},"sources":3,"official":3,"filed":"2026-09-29","updated":"2026-10-11","orgs":["Anthropic"]},{"id":"2025-02-24-claude-3-7-sonnet-claude-code","url":"https://postcutoff.com/e/2025-02-24-claude-3-7-sonnet-claude-code/","date":"2025-02-24","date_precision":"day","short_title":"Claude 3.7 Sonnet (hybrid reasoning) and Claude Code preview","deck":null,"takeaway":"Claude Code became a breakout product and a template for terminal coding agents (Codex CLI, Gemini CLI), shifting software development toward agent delegation.","category":"model-release","category_label":"Model releases","importance":4,"confidence":"high","status":{"key":"confirmed","labels":["Confirmed"]},"sources":2,"official":2,"filed":"2026-09-29","updated":"2026-09-29","orgs":["Anthropic"]}],"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/anthropic-claude-opus-4"}