Claude Duet, an off switch for web fetch, and SDK 2.0

What happened. On 21 October Anthropic opened a research preview of Claude Duet, a separate app where Claude acts on its own. It sends a short brief each morning from your connected apps, checks them every few hours, keeps working after you close the app, and asks before it sends a message, makes a payment, signs a document or deletes anything. It's included in Pro and Max, US subscribers first, by waitlist, and can reach over 6,000 connectors and plugins. 9to5Mac reports it isn't on Team or Enterprise yet.

Why it matters. This is the shape most owners want: something that reads the inbox, the calendar and the books and tells you what needs you. One catch. It shares your plan's usage limits and the background checks count, so on Pro it eats into the allowance your quotes and follow-ups use.

What to do this week.

1. Nothing to buy or install until it reaches Australia.
2. If you want the morning brief now, a scheduled task in Cowork does most of it: open Cowork, press Schedule, and describe the 7am brief you want from your email and calendar.
3. Decide now which apps an agent may read and which it may only draft for, so you're ready the day Duet arrives.

What happened. On 20 October Anthropic added a switch to the Capabilities page of the Claude Console that turns web fetch off for the whole organisation. With it off, an API request that includes the web fetch tool fails with a 400 error. With it on, the same page takes a list of allowed or blocked domains. It lands eleven days after Anthropic disclosed that one of its models filed a fake police tip and promised to restrict its fetch tools.

Why it matters. An automation built in n8n, Make or a Python script runs on an API key from the Console, and Anthropic's web fetch tool is how an agent built that way opens a web page. Not every automation has it on, which is a question for whoever built yours. Where it is on, an email the agent reads can send it to a site you never named. The off switch, or a list of the four or five sites it needs, closes that door without touching the code.

What to do this week.

1. Ask whoever built your automations: do they run on a Claude API key, and who's the admin on that Console account.
2. If none of them needs the web, turn web fetch off. The setup section below walks through it.
3. If one does, write down the sites it needs and allow only those.

What happened.

• The Claude SDKs jumped a major version on 21 October: API version 2026-10-21, sent by default by Python SDK 2.0.0, TypeScript SDK 1.0.0 and new majors in five other languages. It rejects the temperature, top_p and top_k settings, and the SDKs move from the MIT licence to Apache 2.0. A script keeps its old API version until someone upgrades the SDK.
• Agent Skills are no longer Anthropic's. On 22 October Anthropic donated the skill format, its name and agentskills.io to the Agentic AI Foundation, where MCP already lives. More than 70 platforms read it, with 1 million skills published and nearly 280 million installed. Last week's allow sheet is one of them.
• The Claude desktop app shipped on 20 and 22 October (changelog): a fix for Claude not finding your plugins and skills in scheduled tasks, connector tools that need a person now ask only on the in-app card so a scheduled task carries on without them, and a Storage page in Settings that frees disk space.
• Claude Haiku 4.5 passed its earliest retirement date, 15 October, with no notice posted. It's still running.

Why it matters. The scheduled-task fix is the one to notice. If a skill you uploaded seemed to do nothing when a task ran on its own, that was the app, not you. The SDK change breaks nothing by itself, only on the day a well-meaning person runs an upgrade.

What to do this week.

1. Install the desktop app update when it prompts you, then run one scheduled task that uses a skill and read what it produced.
2. Tell whoever maintains your Claude scripts to pin the SDK version and read the 2026-10-21 migration page before upgrading.