Claude Sonnet 5 API 2026: Anthropic New Coding Model, Pricing, and CodeFast Guide
Anthropic added Claude Sonnet 5 to the API on June 30, 2026: the `claude-sonnet-5` model ID, 1M context, 128K output, adaptive thinking, and migration-sensitive API behavior. This guide explains official pricing, migration notes, and how to use it through CodeFast Claude Max API.
Claude Sonnet 5 is Anthropic next-generation Sonnet model added to the API on June 30, 2026. Its official model ID is `claude-sonnet-5`, and Anthropic positions it as its strongest option for code, agentic workflows, and computer use. It keeps the Sonnet balance of speed and intelligence while aiming for more consistency in long-running tool-using agent tasks.
This launch matters especially for Claude Code, Cursor, terminal agents, and backend AI products. Sonnet 5 is not just a better answer model; it is a new production target that should be evaluated together with long context, adaptive thinking, token behavior, and migration rules.
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