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

With no annotations, this dimension is carried fully by the description. The sentence 'Query discarded' adds a privacy-relevant behavioral note, which is useful. However, it does not disclose possible side effects, error conditions, or what happens when multiple parameters are provided.

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 terse sentences, front-loaded with the main behavior and then a data-handling note. No filler or redundant explanation. This is appropriately concise for the size of the tool 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?

The description is too thin for the context: nine optional parameters, no output schema, and no annotation are available. It does not confirm the output type, the precise parameter to use, or whether ignoring other parameters is acceptable. Leaving the agent to infer the input and return shape creates a real risk of incorrect invocation.

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 coverage is 100%, so parameter descriptions already carry most of the meaning. The description only re-emphasizes that the query is discarded, which adds little beyond the schema. The presence of nine optional parameters makes it less obvious which one represents 'the search query,' but the schema's own wording helps fill that gap.

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 a specific operation: count characters in a search query. It pairs a concrete verb with the object, which is enough to tell what the tool does. It does not explicitly differentiate from sibling tools, though the name and wording make the core purpose obvious.

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 given for when to prefer this tool over the many sibling tools (e.g., hn-front-count, memory-key-count, or other shape validators). The description also does not mention an alternative or exclusion condition. The agent has to infer usage from the name alone.

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