Build an agent that completes a full task end to end: reads data, makes decisions, and takes action with tools.
A tool is any function the agent can call. You describe each tool in plain words: what it does and what inputs it needs.
Example tools: "search_web(query)", "send_email(to, subject, body)", "read_sheet(row)".
The agent reads your descriptions, picks the right tool for the moment, and fills in the inputs. Clear tool descriptions are what make an agent reliable.