Does the description explain when to use this tool, when not to, or what alternatives exist?
The description provides clear context on when to use the tool: for extracting fields from unstructured text. It mentions limits (16,000 chars, 40 fields) and cost, and references the GET alternative for file parsing, helping the agent decide between tools. However, it does not explicitly state when not to use this tool.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.