- Allows Claude to search the web and use the results to inform responses - Provides up-to-date information for current events and recent data - Returns search result information formatted as search result blocks - Use this tool for accessing information beyond Claude's knowledge cutoff - Searches are performed automatically within a single API call Usage notes: - Domain filtering is supported to include or block specific websites - Web search is only available in the US - Account for "Today's date" in . For example, if says "Today's date: 2025-07-01", and the user wants the latest docs, do not use 2024 in the search query. Use 2025.