Stainless acquisition, KPMG alliance, self-hosted agent sandboxes

Anthropic has acquired Stainless, the developer-tooling startup founded in 2022 by former Stripe engineer Alex Rattray that has generated every official Anthropic SDK since the API launched. Stainless auto-generates production-ready SDKs across Python, TypeScript, Go, Java, and Kotlin from API specs and is also used by OpenAI and Google. The deal is framed as a vertical integration into agent connectivity — "agents are only as useful as what they can connect to." Terms were not officially disclosed but reported at over $300M.

KPMG and Anthropic announced KPMG Digital Gateway Powered by Claude, embedding Claude directly into KPMG's client delivery platform. Every one of KPMG's 276,000+ global employees will gain access to Claude, with an initial focus on tax and private equity clients. Anthropic named KPMG a preferred consultant for PE, and the two companies will co-develop new Claude-powered products for portfolio companies.

PwC will roll out Claude Code and Cowork starting with U.S. teams and expanding toward its global workforce of hundreds of thousands. The companies are establishing a joint Center of Excellence and a program to train and certify 30,000 PwC professionals on Claude.

Anthropic announced a $200 million partnership with the Gates Foundation, extending Claude's reach into philanthropic and global health use cases. Specific focus areas were not fully detailed in the initial announcement.

Self-hosted sandboxes let tool execution run inside your own infrastructure or via managed providers (Cloudflare, Daytona, Modal, Vercel) while Anthropic's cloud still handles the agent loop — orchestration, context, and error recovery. MCP tunnels let agents reach private internal MCP servers such as databases, internal APIs, and ticketing systems via a single encrypted outbound connection with no public endpoints required. Note: self-hosted sandboxes are not yet available on Claude Platform on AWS, and Memory is not yet supported in self-hosted sessions. Request access for MCP tunnels in the Claude Console.

The /simplify command is now /code-review. It reports correctness bugs at a chosen effort level (e.g., /code-review high). Pass --comment to post findings as inline GitHub PR comments, making it easy to surface issues directly in your pull request review flow.

Pinned background sessions (Ctrl+T in claude agents) now stay alive when idle and are restarted in place when Claude Code updates, so your long-running sessions are no longer dropped by routine version bumps. Sessions are shed under memory pressure only after non-pinned sessions are cleared first.

New --json flag on claude agents lists all live Claude Code sessions as structured JSON, useful for tmux-resurrect integrations, terminal status bars, and custom session pickers. Also added agent_id and parent_agent_id attributes to claude_code event attributes for better tracing.

A regression introduced in v2.1.147 caused the Bash tool to return exit code 127 on every command for some users, breaking shell-dependent workflows. The fix ships in v2.1.148. Update via claude update or your package manager.

Fast mode now supports Claude Opus 4.7. Set speed: "fast" with model: "claude-opus-4-7" and include the fast-mode-2026-02-01 beta header for significantly faster output token generation at premium pricing. Pricing and rate limits match Opus 4.6 fast mode. Join the waitlist for access.

Pass diagnostics.previous_message_id on any Messages API request and the response now includes a cache_miss_reason field explaining exactly where the prompt cache prefix diverged from the previous turn. Include the cache-diagnosis-2026-04-07 beta header in your requests to enable this.

Claude is now available inside QuickBooks, PayPal, HubSpot, Canva, Docusign, Google Workspace, and Microsoft 365 with ready-to-run workflows for payroll, invoicing, sales, marketing, and month-end close. The launch targets small business owners who want AI embedded in the tools they already use daily.

Claude released a major legal-focused MCP expansion covering research, contracts, discovery, matter management, and legal aid. Legal professionals have become the most engaged Claude Cowork users of any knowledge-work function, prompting Anthropic to double down with a much larger set of tools and open customization options.

Code with Claude London ran May 20–21 with Day 1 keynotes and breakout sessions streamed live on YouTube. Sessions covered agentic development with teams from Asana, Cursor, GitHub, Replit, and Vercel. The roadshow continues with Code with Claude Tokyo on June 5–6.