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

No annotations exist, so the description must carry the full behavioral burden. It states the query is discarded, but that largely repeats the input-schema description for the `query` parameter. It does not disclose what the tool returns, whether other parameters are ignored, or the absence of side effects/storage beyond this one pointer.

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 text is two short, front-loaded sentences with no filler or redundant broader structure. Each sentence conveys a distinct piece of information: the operation and the data disposal behavior. It is appropriately compact for the tool's stated purpose.

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?

With no annotations, no output schema, and nine optional parameters, the description is too sparse to be complete. It neither states the output format (e.g., returns an integer length) nor clarifies that the other eight parameters are ignored/or dispositive, so an agent may reasonably be uncertain what to pass or what back.

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 description adds only minimal semantic value by naming 'search query', which loosely maps to the `query` parameter, but it does not clarify what happens when multiple optional parameters are supplied or how to handle the query field beyond its already-described discard behavior.

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 uses a specific verb and resource: 'Count characters in a search query,' which is distinct from siblings like hn-front-count or memory-key-count. It does not explicitly name an alternative, so it lacks full sibling differentiation, 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?

No guidance is provided about when to choose this tool over other counting or shape-checking siblings (e.g., hn-front-count, memory-key-count). There are no usage prerequisites, exclusionary conditions, or references to alternative tools.

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