May 2026 Newsletter
Simon Willison's Weblog13 days agoCommentarySimon Willison sent the May 2026 edition of his sponsors-only monthly newsletter. Topics include rising AI costs, Anthropic's strong month, and somewhat disappointing model releases. The issue also covers conferences, podcasts, the launch of Datasette Agent, progress on Datasette, tools he is using, and miscellaneous extras. An April issue is available as a public preview.
How we contain Claude across products
Simon Willison's Weblog14 days agoCommentaryAnthropic explains how process sandboxes, VMs, filesystem boundaries, and egress controls limit what Claude agents can access. Claude.ai uses gVisor; local Claude Code uses Seatbelt on macOS and Bubblewrap on Linux; Cowork runs in a full VM. Simon Willison highlights the documentation quality, notes a previously missed file-exfiltration path, and plans to revisit Anthropic's open-source srt tool.
Anthropic Releases Claude Opus 4.8 With Integrity Upgrades and Dynamic Workflows
INSIDE 硬塞 AI16 days agoReleaseAnthropic released Claude Opus 4.8 as a rapid iteration focused on stronger integrity and reliability for high-risk tasks. The company also previewed Dynamic Workflows, a feature designed to coordinate multiple agents on large-scale jobs such as code migration. The article mentions Mythos entering a countdown toward unblocking, but does not provide detailed availability or product specifics.
Anthropic Series H Valuation Reaches $965B, Backed by Memory Giants★ 78
INSIDE 硬塞 AI16 days agoBusinessAnthropic completed a $65 billion Series H round, bringing its valuation to $965 billion and reportedly surpassing OpenAI. The round included strategic investments from memory makers Micron, Samsung, and SK Hynix. The news highlights how frontier AI companies are increasingly tied to hardware and memory supply chains, as investors continue backing foundational model competition.
Anthropic raises $965B Series H, releases Opus 4.8 and Dynamic Workflows/ultracode
Latent Space16 days agoBusinessThe visible AINews item centers on Anthropic, claiming a $965B Series H alongside Opus 4.8 and Dynamic Workflows/ultracode releases. The available body text is extremely brief, offering only the editorial line “Total Anthropic victory!” It signals a major Anthropic narrative across capital, Claude models, and developer workflows, but provides no detailed specs, benchmarks, investor terms, or availability information.
Anthropic's run-rate revenue hits $47 billion★ 76
Simon Willison's Weblog16 days agoBusinessSimon Willison highlights Anthropic’s latest Series H announcement, where the company says run-rate revenue crossed $47 billion earlier in May. He traces prior disclosures: about $9 billion at the end of 2025, $14 billion in February 2026, and over $30 billion in April. The post also addresses skepticism, arguing that these numbers appeared in fundraising announcements, where knowingly misleading investors would be securities fraud.
Claude Opus 4.8: "a modest but tangible improvement"
Simon Willison's Weblog16 days agoReleaseAnthropic shipped Claude Opus 4.8, and Simon Willison highlights the unusually restrained release language: a “modest but tangible improvement.” The model keeps most Opus 4.7 pricing and specs, while evaluations suggest it is more likely to flag uncertainty and less likely to ignore flaws in code it wrote. Developer-relevant changes include mid-conversation system messages and a lower prompt-cache minimum of 1,024 tokens.
llm-anthropic 0.25.1
Simon Willison's Weblog16 days agoReleaseSimon Willison released llm-anthropic 0.25.1 with support for the new Claude Opus 4.8 model, exposed as claude-opus-4.8. The release adds a -o fast 1 option for Anthropic fast mode, limited to organizations that have the feature enabled. It also changes default max_tokens behavior so each model now defaults to its maximum output instead of 8,192.
Anthropic releases Opus 4.8 with new Dynamic Workflows tool
TechCrunch AI17 days agoReleaseAnthropic has released a new Opus model, Opus 4.8, alongside a tool called Dynamic Workflows. The report says the tool is designed to coordinate swarms of subagents, pointing to a focus on multi-agent orchestration. The source does not provide benchmarks, pricing, API details, availability, or concrete use cases.
Claude’s new model is more ‘honest’ when it messes up
The Verge AI17 days agoReleaseAnthropic is releasing Claude Opus 4.8 and highlighting the model’s “honesty” as a key improvement. The company says it trains its models to avoid unsupported claims, addressing a broader issue where AI systems sometimes jump to conclusions. Based on the provided excerpt, the update is positioned around reliability and uncertainty handling rather than a specific new tool or benchmark result.
Import AI 458: Reckoning with the future; and a singularity story★ 74
Import AI (Jack Clark)19 days agoCommentaryThis Import AI issue is a long essay and fiction piece about living through rapid AI progress. Clark uses personal experience and Anthropic’s internal use of Claude to show work shifting toward delegation, verification, observability, and agent management. He then offers speculative 2026-2028 predictions around biology, autonomous companies, robotics, recursive self-improvement, and a positive singularity story focused on healthcare.
Anthropic 營收爆發成長！傳估值直逼 1 兆美元，挑戰全球最貴 AI 新創寶座★ 85
INSIDE 硬塞 AI22 days agoBusinessAccording to the latest reports, AI startup Anthropic has seen explosive revenue growth and is actively engaged in negotiations for a new funding round…
SpaceX 提交 S-1 招股書：揭露 Anthropic 每月支付 12.5 億美元租用 Colossus 算力，並證實 Grok 5 訓練中★ 90
Simon Willison's Weblog24 days agoBusinessWell-known tech expert Simon Willison has cited SpaceX's latest S-1 IPO prospectus filed with the U.S. Securities and Exchange Commission (SEC), which reveals…
Anthropic 年成長達 10 倍，與其他科技巨頭裁員超過 10% 形成強烈對比★ 75
Latent Space36 days agoBusinessIn the current technology industry and broader economic environment, an extreme and striking "dual-track" divergence (dichotomy) is playing out. On one hand…
Anthropic 與 xAI 簽署 50 億美元 Colossus 算力合約，ARR 暴增 8000%★ 90
Latent Space38 days agoBusinessThis is a heavyweight partnership that has shaken the AI industry. According to the latest report from Latent Space, AI unicorn Anthropic has reached an…
Vercel AI Gateway 正式支援 Claude 4.7 Opus 模型★ 75
Vercel Changelog59 days agoReleaseVercel announced in its Changelog that its AI Gateway service now officially supports Claude 4.7 Opus, the latest flagship large language model released by…
Model Context Protocol (MCP) 詳解：常見問答集 (FAQ)★ 85
Vercel Changelog324 days agoTutorialAs AI applications become more widespread, how to allow large language models (LLMs) to securely and efficiently access enterprise internal data or external…