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

No annotations are provided, so the description carries the full disclosure burden. It states the query is discarded, hinting at non-persistence, but it does not say what is returned, whether the other accepted parameters are ignored or processed, or whether any validation or fetching side effects occur.

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 action is front-loaded and the discard note is helpful. The brevity is efficient, though it leaves semantic and contextual gaps scored elsewhere.

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?

This is a high-complexity definition: nine optional parameters, no annotations, no output schema, and many siblings. The description does not explain how to select a parameter, what the successful response looks like, or what happens when multiple parameters are supplied, so an agent cannot confidently invoke it from the definition 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?

Schema description coverage is 100%, so each parameter is already documented, including query as 'Search text; discarded after the length check.' The description adds no parameter-level detail beyond aligning 'search query' with the query field, so the baseline of 3 applies.

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 names a concrete operation ('Count characters') and a resource ('a search query'), and 'Query discarded' adds scope. It is clear on its own, though it does not explicitly distinguish itself from sibling count/length 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 on when to prefer this tool over alternatives, no exclusions, and no mention of prerequisites. The implied use case, needing a character count of a search query, is too thin given the large sibling set and nine optional input parameters.

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