Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations provided, the description carries the full burden. It discloses the tool's counting behavior (total, excluding whitespace, pages) but does not explicitly mention that it is read-only or has no side effects. Since it is a counting tool, this is mostly inferable, but some edge cases (e.g., whitespace definition) are not addressed.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single well-structured sentence that front-loads the core purpose and enumerates the output types efficiently. No wasted words or repetition of schema details.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the tool's simplicity (one parameter, no output schema, no annotations), the description explains the key return values (total, excluding whitespace, pages). It is mostly complete but could benefit from clarifying what counts as whitespace or how 'pages' is formatted, though the 400 chars/page note helps.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The schema has zero description coverage and only a single 'text' property. Although the description does not mention the parameter by name, it refers to 'text' directly, making clear the input is the string to be counted. This adds essential meaning beyond the bare schema definition.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool counts characters in text and specifies three distinct counting modes: total, excluding whitespace, and manuscript pages. The verb 'count' and resource 'Japanese (or any) text' are explicit, and it is easily distinguished from sibling tools which handle conversion or lookup tasks.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description sets clear context by noting it works on Japanese or any text, implying when to use it. However, it does not explicitly mention when not to use it or name alternative tools, though the sibling tools are clearly different in purpose.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.