Anthropic

The Messages API is the foundation of everything you build with Claude. Every feature — tool use, vision, streaming, caching — goes through this API. Understanding it deeply will make every other article in this series easier. This is Article 7 in the Claude AI — From Zero to Power User series. You should have completed Article 2: Getting Started before this article. By the end of this article, you will know how to build multi-turn conversations, stream responses in real time, and track your token usage. ...

Anthropic just built its most powerful model — and decided not to release it to the public. Claude Mythos Preview is real, and the reason it’s restricted has nothing to do with business strategy. It found thousands of zero-day vulnerabilities across every major operating system and every major web browser. Some of those bugs had been hiding for decades. What Is Claude Mythos Preview? Claude Mythos Preview is Anthropic’s most capable model, released April 7, 2026 — but only to a restricted set of security partners. ...

Claude Code is smart. But it does not know your project. It does not know your coding style, your build commands, or your project structure. That is what CLAUDE.md fixes. This is Article 6 in the Claude AI — From Zero to Power User series. You should have completed Article 3: Claude Code CLI before this article. By the end of this article, you will know how to write CLAUDE.md files that make Claude Code work like a teammate who already knows your codebase. ...

Anthropic launched the Advisor Strategy on April 9, 2026 — a way to get near-Opus intelligence in your AI agents at a fraction of the cost. The idea is simple. Instead of running Opus on every request, you pair a cheaper model with Opus as an on-demand advisor. The cheap model does all the work. Opus only steps in when needed. How It Works You have two roles: Executor — Sonnet or Haiku. Runs every turn. Calls tools, reads results, makes decisions. Advisor — Opus. Runs on-demand only. Reviews the shared context and sends guidance when the executor is stuck. The executor and advisor share the same context: the system prompt, tool definitions, full conversation history, and all prior tool results. When the executor hits a hard decision, it calls the advisor tool. Opus reviews the full context and sends back a plan or correction. Then the executor continues. ...