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

No annotations are present, so the description carries the full behavioral disclosure burden. It only says 'Query discarded,' which partly duplicates the existing schema note on `q`, and it fails to state what the tool returns (e.g., a numeric character count) or how it handles missing or invalid input.

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 compact and front-loaded with the main operation in the first sentence. The second sentence is brief and adds a privacy-relevant note, though it is somewhat redundant with the schema's note that `q` is discarded.

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 tool with no output schema and no annotations, the description should specify the expected return value, the relevant input parameter, and when to use it among many siblings. The current text covers none of those, leaving an agent to infer too much from the schema alone.

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 input schema documents every parameter with a description, so schema coverage is high and the baseline is 3. The description adds general semantic context by implying the target is the `q` field, but it does not explicitly name that parameter or clarify how the other schema fields relate.

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 an action ('Count characters') and a target resource ('a search query'), which matches the tool name and is distinct from sibling shape/validation tools. It could be stronger by explicitly naming the `q` parameter, but the core purpose is unambiguous.

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 siblings like normalize-url, validate-json, or domain-shape. The description provides no context about the related 'shape check' tools or when counting query length would be the appropriate choice.

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