Claude

September 2026 update: Since April we got Opus 4.8, Sonnet 5, Opus 5 and a new Fable 5 / 5.1 tier above Opus — all with 1M context. Claude Code limits doubled and auto mode is now the default. See Claude Code over the summer and Fable 5 explained. The text below is the original spring 2026 review.

Why Claude?

Claude from Anthropic is an AI assistant built with an emphasis on accuracy, safety, and the ability to work with extensive context. After a year of intensive use, I consider it the best choice for professional work — especially programming, document analysis, and structured tasks.

Model lineup

Claude Opus — the most powerful model. Excels at complex reasoning tasks, code analysis, and situations that demand deep understanding of context. Slower, more expensive, but the results are noticeably better.

Claude Sonnet — the best performance/price ratio. For 90% of tasks, Sonnet is sufficient and significantly faster than Opus. I recommend it as the default model.

Claude Haiku — the fastest and cheapest. Ideal for simple classifications, data extraction, and real-time applications where latency matters.

Extended thinking

Claude Opus and Sonnet let you turn on explicit reasoning — the model "thinks" before answering and shows you its thought process. Unlike OpenAI o1/o3, where the chain-of-thought is hidden, with Claude you see the whole sequence.

In practice, this fundamentally improves:

• Math and logic problems
• Debugging complex code
• Deciding between multiple options
• Analyzing contracts and legal texts

Claude Code — killer feature for developers

Claude Code is a CLI tool that changes the way I program. It's not autocomplete like Copilot — it's an agent that understands the whole project:

• Navigates the repository and understands the structure
• Writes and edits files based on high-level instructions
• Runs tests and fixes the errors it finds
• Commits and creates PRs with reasonable commit messages
• MCP integrations for access to databases, APIs, Figma, and other tools

This site was built entirely via Claude Code — from scaffold through components to the Docker configuration and deploy on Vercel.

API and integrations

The Claude API is straightforward and well-documented. It supports:

• Messages API with system prompts and multi-turn conversations
• Vision — analysis of images, screenshots, documents
• Tool use — structured calls to external functions
• Streaming for real-time answers
• Batches for bulk processing

Works great with the Vercel AI SDK — one line of code to switch between Claude, GPT, or Gemini.

Comparison with ChatGPT

Area	Claude	ChatGPT
Accuracy	Higher, fewer hallucinations	Good, but occasionally makes things up
Code	Excellent, especially with Code	Very good with Copilot
Long documents	Excels (1M)	Good (GPT-6 Astra has 1.05M)
Creativity	Good	Better for creative writing
Ecosystem	Smaller, growing	GPT Store, plugins
Multimodality	Text + images	Text + images + audio + video

Who is Claude for?

• Developers — Claude Code is a game changer
• Analysts — accurate work with data and documents
• Lawyers/consultants — reliable analysis of extensive texts
• Marketers — consistent and factually accurate content
• Anyone who needs reliability over creativity

Verdict

Claude is the best AI assistant for professional work. The combination of accuracy, long context, extended thinking, and Claude Code makes it a tool I can no longer imagine my workflow without. If you're a developer or work with text and data, try it — and start with Sonnet.