Anthropic Release notes and new features

Code written for Claude Sonnet 5 can break on Claude Sonnet 5.5 in five ways

Code written for Claude Sonnet 5 can break on Claude Sonnet 5.5 in five ways. To turn off up-front thinking, send thinking: {"type": "between_tools"} instead of "disabled", at high effort or below. Forced tool use (tool_choice types any and tool) returns a 400 error. Thinking blocks are tied to the model and the conversation.

• Code written for Claude Sonnet 5 can break on Claude Sonnet 5.5 in five ways
• Thinking blocks that Claude Sonnet 5.5 produces work only in the account that produced them, or in an account
• We've launched Claude Sonnet 5.5 (claude-sonnet-5-5)

Claude Agent SDK 0.2.161

Internal/Other Changes Updated bundled Claude CLI to version 2.1.284 PyPI: https://pypi.org/project/claude-agent-sdk/0.2.161/ bash pip install claude-agent-sdk==0.2.161

Claude Code 2.1.284

- Added Claude Sonnet 5.5 (claude-sonnet-5-5), now the default Sonnet model on the Anthropic API , 1M context, $2/$10 per Mtok with $0.20/Mtok cache reads Added a "Yes, but ask again next time" answer to auto mode's prompt before a read outside the working directories, so you can allow that one read and still be asked about later ones Added dollar amounts...