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

The description states 'Query discarded,' implying the operation is non-destructive and side-effect-free. However, it does not describe the return value (e.g., whether it returns the count as an integer) or any potential errors. With no annotations, this is only partial transparency.

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 extremely concise, consisting of two short sentences with no unnecessary words. It efficiently conveys the core function and the disposal of the query.

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?

For a simple count operation, the description is mostly complete, but it omits details about the return format and does not address the purpose of the many extraneous parameters. The lack of an output schema leaves the agent guessing about the exact result type.

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 describes all 9 parameters, but only 'query' is relevant to the tool's purpose. The other parameters (ref, url, city, feed, host, json, path, zone) are decoys and are not explained in the tool description, which could mislead an agent into thinking they are used. Schema descriptions exist but do not clarify that they are irrelevant.

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 action ('Count characters') and the resource ('a search query'), but it does not explicitly name the parameter that holds the query, though the schema includes a 'query' field. This is slightly ambiguous given the presence of many other parameters.

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?

There is no guidance on when to use this tool versus any of the 25 sibling tools. No alternatives are mentioned, and the description provides no context for selecting this tool over others.

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