Claude Sonnet 5.5 is live on OpenRouter
OpenRouter now offers Anthropic’s Claude Sonnet 5.5. OpenRouter says it is significantly smarter than Sonnet 5, writes more clearly, and is 30% faster and about 30% cheaper for most work.
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View all AI newsPi directs users to run pi update --models as Claude introduces Sonnet 5.5
Pi tells users to run pi update --models alongside Claude’s introduction of Claude Sonnet 5.5. Claude says the model is the second in the Claude 5.5 family, runs more than 30% faster than Sonnet 5, and costs up to 30% less for most work.
ClaudeDevs extends preserved thinking on Sonnet 5.5 against account switching
ClaudeDevs is extending preserved thinking with Sonnet 5.5 so thinking stays in the organization that generated it. Switching accounts mid-session makes Claude reread the session and generate new thinking.
Claude Sonnet 5.5 is generally available in GitHub Copilot
GitHub says Anthropic’s Claude Sonnet 5.5 is now generally available in GitHub Copilot, including the Copilot app, CLI, and code. In GitHub’s early testing, it matched Sonnet 5 on coding tasks while using fewer steps, tokens, and tool calls and finishing faster.
Unused Pro, Max, and Team resets can be applied before Oct 22
ClaudeDevs says every Pro, Max, and Team user was granted a reset last Tuesday. Anyone who has not used it can still apply it at any time before Oct 22. Sonnet 5.5 is available now in the Claude Platform and Claude Code.
Sonnet 5.5 shows up to 20% lower Claude Platform costs and more Claude Code usage
ClaudeDevs says Sonnet 5.5 has produced as much as 20% lower costs on the Claude Platform and 30% more usage in Claude Code. Claude calls it the second Claude 5.5 model, more than 30% faster than Sonnet 5 and up to 30% cheaper for most work.
Claude Sonnet 5.5 is now available in v0
v0 now offers Claude Sonnet 5.5. Claude says it is the second model in the Claude 5.5 family, a clear upgrade over Sonnet 5 that runs more than 30% faster and costs up to 30% less for most work.
Claude Sonnet 5.5 is available everywhere; Haiku 5.5 is coming
Claude says Claude Sonnet 5.5 is available everywhere today. Claude Haiku 5.5 is expected to join the Claude 5.5 family in the coming weeks.
Claude says Sonnet 5.5 matches or beats Sonnet 5 on most alignment measures
On Claude’s automated behavioral audit, Sonnet 5.5 improves on or matches Sonnet 5 on most alignment and honesty measures. It is also the first Sonnet model with cyber safeguards and fallbacks like those on Claude’s most capable models, and Claude says routine software development is unaffected.
Paper finds personal AI agents recommend costlier options to users inferred as wealthy
A new paper reports that eight of 13 models chose more expensive flights, health insurance, or graduate-program options for users they inferred were wealthy, even when the request stayed identical. With Claude Opus 4.8, the gaps reach $198 per flight and $284 per month for insurance.
Claude Opus 5.0 declined an IP-sharing route in Perplexity’s SPACE tests
Perplexity says Claude Opus 5.0 identified an IP-sharing route in its SPACE evaluation and declined to use it. Fable and GPT-6 Astra refused the tasks outright.
One plugin discovery experience will roll out across Claude and Claude Code
ClaudeDevs says a single discovery experience will roll out across Claude and Claude Code over the coming weeks, and describes plugins as the main way for third-party developers to extend Claude.
ClaudeDevs adds a portal for submitting and tracking Claude plugins
Developers can submit a Claude plugin, follow its review, and view usage in a new portal. ClaudeDevs says plugins package MCP and skills, and that MCP usage across Claude products is up 110x this year.
Polymarket says Grok generates 59.5% of Coinbase AI-agent trading volume
In Polymarket’s comparison of notional volume, Claude accounts for 13.4% and ChatGPT for 1.5%. No time period is stated.
ClaudeDevs says Opus 5.5 is 20% cheaper per token and 60% cheaper on cache reads
ClaudeDevs says Opus 5.5 costs 20% less per input and output token than Opus 5, and 60% less on cache reads. It also published a calculator for estimating Claude Code task cost from /usage.
Claude completes a nine-loop calculation in planar N=4 super-Yang-Mills
Anthropic says one prompt sent Claude through days of largely unsupervised work in Claude Science, producing a nine-loop scattering-amplitude result that Lance Dixon independently verified, at a total cost of a few thousand dollars.
Runway MCP connects to Claude for image and video generation
Runway MCP can be connected directly to Claude, including Claude Opus 5.5, to generate images and videos with Gen-4.5, Seedance 2.5, GPT Image 2, Kling, and other models.
Arena.ai says Claude Opus 5.5 is easier to read than Opus 5 but writes longer answers
Arena.ai compared high-reasoning Text Arena outputs and says 10 of 12 writing measures moved in a better direction from Claude Opus 5 to Opus 5.5. Average answers grew from 453 to 481 words, while hedges such as “perhaps” rose 97%.
Claude Tag in Slack adds personal connectors
Claude Tag in Slack can use personal connectors to securely open Drive documents, Salesforce accounts, and Warehouse tables a user already has access to. Teams access was available on September 24, 2026, with Enterprise access scheduled for the following week.
Meta AI pairs action agents with dedicated memory agents
DeepLearning.AI reports that Meta AI uses dedicated memory agents to record tools and past errors and insert short reminders, raising Claude Sonnet 4.5 benchmarks from 37.6% to 45.9%.