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

The description explicitly states 'Query discarded,' indicating no side effects or persistence. However, it does not mention any other behavioral aspects like read-only nature or error handling.

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 a single concise sentence without fluff. It front-loads the tool's core action and result.

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 lacks an output schema and the description does not mention what the output is (e.g., a number). Given the simple nature, this is a minor gap, but the mismatched schema parameters reduce overall completeness.

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?

Although all 9 parameters have descriptions, the descriptions are misleading and unrelated to the tool's purpose. For example, 'url' says 'HTTPS URL to normalize or cite' and 'ref' says 'Git ref name; discarded after the shape check,' which are irrelevant to counting query characters. This could confuse an agent into thinking these parameters are meaningful.

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 the tool counts characters in a search query and discards the query. This is a specific verb+resource combination that distinguishes it from sibling count tools.

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?

The description implies usage when character count of a search query is needed, but provides no explicit comparison to alternatives or when-not-to-use guidance. Sibling tools like memory-key-count or hn-front-count are not referenced.

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