Tool

Tool: A function an MCP server offers for the model to call, with a name, description and input schema. Example: Browserbase's tools are navigate, act, observe, extract, start and end. Next in the glossary is Tool annotations: Hints on a tool such as readOnlyHint and destructiveHint that tell clients how risky a call is.

Definition

A function an MCP server offers for the model to call, with a name, description and input schema.

Example, with source

Browserbase's tools are navigate, act, observe, extract, start and end. (docs.browserbase.com, read 4 November 2026)

Where it appears on this site

• MCP
• Tool descriptions and agent success

Neighbouring terms

• Tasks extension: An official MCP extension for long-running operations with polling and durable handles, moved out of core in 2026-07-28.
• Tool annotations: Hints on a tool such as readOnlyHint and destructiveHint that tell clients how risky a call is.
• WebMCP: A draft browser API for pages to register JavaScript tools that an in-browser agent can call.