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

With no annotations, the description carries the behavioral burden. 'Query discarded' usefully signals that the input is not persisted and the operation has no lasting effect. However, it does not clarify whether the other eight optional parameters are ignored or how they interact with the count, nor what the function returns.

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?

Two short sentences with no filler; the core action is front-loaded and the disposal note adds useful behavioral context without unnecessary words.

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?

The tool has nine optional parameters and no output schema, yet the description does not name the primary input parameter, clarify that the unrelated fields can be omitted, or describe the return value. Some schema parameter descriptions, such as url 'to normalize or cite', could mislead an agent into thinking they affect this tool's behavior.

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 schema already documents each parameter, including that query is 'discarded after the length check.' The description adds no parameter-level meaning beyond this, so the baseline of 3 is appropriate.

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 action and resource: 'Count characters in a search query', which goes beyond the tool name and is not a tautology. It is clear what the tool does, but it does not distinguish itself from sibling counting/validation tools such as memory-key-count or hn-front-count.

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 about when to prefer this tool over alternatives, no when-not-to-use conditions, and no mention of sibling tools. The only implicit hint is that the query is discarded, suggesting it is for length-only checks, but that is not explicit enough.

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