Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
The tool is simple (one parameter, no output schema). The description compensates for the missing output schema by enumerating all computed statistics (character counts, word/sentence/paragraph counts, reading time, average word length, longest word). It also includes operational context ('keyless, offline') sufficient for an agent to invoke correctly.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.