Claude 3.7 Sonnet (hybrid reasoning) and Claude Code preview
Confirmed
Importance: major (4 of 5)The takeaway
Anthropic released Claude 3.7 Sonnet, the first hybrid reasoning model able to answer instantly or use visible extended thinking, together with a research preview of Claude Code, an agentic coding tool that runs in the terminal.
Status
- Claim
Confirmed
- Our reporting
- High confidence
- Importance
- Major (4 of 5)
- Last verified
- 29 September 2026
Your AI and this story
- GPT-6 AstraIn its training data
- Claude Opus 5.5In its training data
- Gemini 4 HydrogenIn its training data
- Grok 4.7In its training data
It happened before the cutoffs of all four assistants, so it can be in their training data.
Key facts
- Released 24 February 2025
- Extended thinking mode with user-controllable thinking budget via API
- SWE-bench Verified: 62.3% (70.3% with custom scaffold), per Anthropic
- Claude Code launched as a limited research preview; generally available with Claude 4 in May 2025
What happened
Anthropic combined fast responses and deep reasoning in one model and shipped a command-line agent that edits code, runs tests and commits on its own.
Why it matters
Claude Code became a breakout product and a template for terminal coding agents (Codex CLI, Gemini CLI), shifting software development toward agent delegation.
Sources
2 sources from 2 sites. Numbers match the chips in the text.
2 sources: 2 primary
Primary
- Claude 3.7 Sonnet and Claude Code (Anthropic)anthropic.com, official
- Claude Code documentationdocs.anthropic.com, docs
Changes
- Filed