Alongside the model, today we're launching three very useful API features for building agents that scale to hundreds of tools without context bloat. - Tool Search Tool - Programmatic Tool Calling - Tool Use Examples Here's how they work:

Tool Search Tool Instead of loading all tool definitions upfront, Claude discovers tools on-demand. Mark tools with defer_loading: true and only pays tokens for tools Claude actually needs. Up to an 85% token reduction and big boost in accuracy on our MCP evals (79.5% to 88.1%)

Programmatic Tool Calling Claude orchestrates tools through code instead of individual round-trips. It writes Python, processes outputs in a sandbox, and controls what enters context.

Tool Use Examples JSON Schema defines what's valid, not what's correct. Now you can show Claude concrete usage patterns directly in tool definitions to improve Claude's accuracy and knowledge when using tools.