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

No annotations are provided, so the description carries the full burden of behavioral disclosure. The phrase 'Query discarded' is the only behavioral trait, and it duplicates the query parameter's schema description ('discarded after the length check'); it adds no new information and does not cover output format, error behavior, or handling of the other accepted parameters.

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 and front-loads the purpose in the first sentence. It is not bloated, though the second sentence is redundant with the schema's query parameter description.

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 ten optional parameters, no output schema, and no annotations, the description is incomplete: it does not specify the return value format, how character length is computed (code points vs UTF-16 units), or how the tool behaves with empty or multiple inputs.

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?

Schema description coverage is 100%, so the baseline is 3. The schema's per-parameter descriptions, especially for 'query', are clear; however the tool description itself does not explain that the length check applies to 'query' only, nor what happens when multiple parameters are supplied.

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 states a specific verb ('Count') and resource ('characters in a search query'), which is enough to understand the core operation. It does not explicitly distinguish itself from similar counting tools like hn-front-count or memory-key-count, but the resource is clearly different.

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 instead of alternatives, no exclusions, and no mention that the 'query' parameter is the operative input among the schema's ten parameters. The agent must infer usage entirely from the parameter descriptions.

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