--- title: Claude Code 3.0 (All Upgrades Explained): You don't KNOW... description: A roundup of Claude Code updates over the past two months: Opus 5 is now the default model with a 1M token context window, cross-session messaging between... canonical: https://daily.dev/posts/claude-code-3-0-all-upgrades-explained-you-don-t-know-about-these-crazy-new-features-yet--ierlvigls twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Claude Code 3.0 (All Upgrades Explained): You don't KNOW about THESE CRAZY NEW FEATURES YET! | daily.dev og:description: A roundup of Claude Code updates over the past two months: Opus 5 is now the default model with a 1M token context window, cross-session messaging between... og:url: https://daily.dev/posts/claude-code-3-0-all-upgrades-explained-you-don-t-know-about-these-crazy-new-features-yet--ierlvigls og:image: https://api.daily.dev/og/posts/iERLViGLS.png og:image:alt: Claude Code 3.0 (All Upgrades Explained): You don't KNOW about THESE CRAZY NEW FEATURES YET! og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Claude Code 3.0 (All Upgrades Explained): You don't KNOW about THESE CRAZY NEW FEATURES YET! **[AICodeKing](https://daily.dev/sources/aicodeking)** · 11 min read · 0 upvotes · 0 comments ## Summary A roundup of Claude Code updates over the past two months: Opus 5 is now the default model with a 1M token context window, cross-session messaging between agents, fork mode for background sub-agents (up to 20 concurrent), a new /design command for UI artboards, a security scanning plugin, auto mode as the default permission mode, a built-in browser and iOS simulator in the desktop app, GitLab support, and self-hosted environments in beta. The video also covers Anthropic's rate limit changes: a 'permanent 25% increase' to weekly limits starting September 14th that is actually a 17% cut compared to the temporary 50% boost currently in effect, which Anthropic itself admitted after initially deleting and reposting the announcement. The presenter also promotes TestSprite, an open-source CLI verifier used to close the agentic feedback loop by testing deployed apps like a real user. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### What are Anthropic's new weekly rate limits for Claude Code starting September 14? Starting September 14, standard weekly limits for Claude Code rise by a permanent 25% over the original baseline on Pro, Max, Team, and seat-based Enterprise plans. However, because the temporary 50% boost in place since May expires on September 13, this actually amounts to a 17% reduction compared to current usage. Anthropic confirmed this math after deleting and reposting its original announcement. _daily.dev helps developers track shifting AI usage limits before they get caught off guard mid-project._ ### What model does Claude Code use by default now and what context window does it support? Claude Opus 5 became the default model in Claude Code, rolling out in late July across Pro, Max, Team, Premium, Enterprise, pay-as-you-go, and API access. It supports a 1 million token context window on the API and on Max, Team, and Enterprise plans, which is especially useful for large codebases. Fast mode also moved to Opus 5, priced at $10 input and $50 output per million tokens. _Developers choosing an agentic coding model check context window and pricing details like these on daily.dev._ ### How does cross-session messaging work in Claude Code? Cross-session messaging lets multiple Claude Code sessions running on the same machine discover and message each other directly, so one session can notify another about relevant changes, such as a renamed database column affecting a payments API. Sessions can be mentioned in a prompt using the @ symbol. It started on macOS and Linux in early August and is now also available on native Windows. _Teams running parallel AI coding sessions follow workflow changes like this through daily.dev._ --- Tags: [#ai-agents](https://daily.dev/tags/ai-agents), [#anthropic](https://daily.dev/tags/anthropic), [#claude-code](https://daily.dev/tags/claude-code) [View this post on daily.dev](https://daily.dev/posts/claude-code-3-0-all-upgrades-explained-you-don-t-know-about-these-crazy-new-features-yet--ierlvigls) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"Claude Code 3.0 (All Upgrades Explained): You don't KNOW about THESE CRAZY NEW FEATURES YET!","url":"https://daily.dev/posts/claude-code-3-0-all-upgrades-explained-you-don-t-know-about-these-crazy-new-features-yet--ierlvigls","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/claude-code-3-0-all-upgrades-explained-you-don-t-know-about-these-crazy-new-features-yet--ierlvigls"},"datePublished":"2026-08-31T13:14:08.703Z","dateModified":"2026-08-31T13:15:02.270Z","description":"A roundup of Claude Code updates over the past two months: Opus 5 is now the default model with a 1M token context window, cross-session messaging between...","image":"https://i.ytimg.com/vi/6m1vJqdsanQ/sddefault.jpg","thumbnailUrl":"https://i.ytimg.com/vi/6m1vJqdsanQ/sddefault.jpg","isAccessibleForFree":true,"articleSection":"AICodeKing","inLanguage":"en","publisher":{"@type":"Organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180}},"author":{"@type":"Organization","name":"AICodeKing","logo":"https://media.daily.dev/image/upload/s--x7nDUfWj--/f_auto,q_auto/v1768208312/logos/aicodeking","url":"https://daily.dev/sources/aicodeking"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/claude-code-3-0-all-upgrades-explained-you-don-t-know-about-these-crazy-new-features-yet--ierlvigls","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":0},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"ai-agents,anthropic,claude-code","timeRequired":"PT11M","video":{"@type":"VideoObject","name":"Claude Code 3.0 (All Upgrades Explained): You don't KNOW about THESE CRAZY NEW FEATURES YET!","description":"A roundup of Claude Code updates over the past two months: Opus 5 is now the default model with a 1M token context window, cross-session messaging between...","thumbnailUrl":"https://i.ytimg.com/vi/6m1vJqdsanQ/sddefault.jpg","uploadDate":"2026-08-31T13:14:08.703Z","duration":"PT11M","url":"https://api.daily.dev/r/iERLViGLS","embedUrl":"https://www.youtube.com/embed/6m1vJqdsanQ"}} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"AICodeKing","item":"https://daily.dev/sources/aicodeking"},{"@type":"ListItem","position":3,"name":"Claude Code 3.0 (All Upgrades Explained): You don't KNOW about THESE CRAZY NEW FEATURES YET!"}]} {"@context":"https://schema.org","@type":"FAQPage","@id":"https://daily.dev/posts/claude-code-3-0-all-upgrades-explained-you-don-t-know-about-these-crazy-new-features-yet--ierlvigls#faq","mainEntity":[{"@type":"Question","name":"What are Anthropic's new weekly rate limits for Claude Code starting September 14?","acceptedAnswer":{"@type":"Answer","text":"Starting September 14, standard weekly limits for Claude Code rise by a permanent 25% over the original baseline on Pro, Max, Team, and seat-based Enterprise plans. 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