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

No annotations are provided, so the description must carry behavioral disclosure. It does state 'Query discarded,' which signals no persistence for that parameter, but it says nothing about the other eight parameters, the return value, or potential side effects. Schema descriptions partially cover this, but the tool description itself is thin.

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 two short sentences with no filler, and the core action is front-loaded. It is efficient, though arguably too terse for a tool with 9 parameters and no annotations.

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?

For a tool with 9 optional parameters, no annotations, and no output schema, the description leaves critical gaps: which parameter to use, what the return value is, and how the other parameters behave. An agent cannot fully determine how to invoke this tool correctly from the description 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 the baseline is 3. The description adds no parameter-level meaning beyond the schema and actually creates ambiguity by mentioning only 'search query' while eight other parameters exist. The schema itself documents each parameter clearly, so the description does not need to compensate.

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 clear verb and resource: 'Count characters in a search query.' However, the input schema exposes 9 unrelated optional parameters, which makes it unclear whether this tool only handles the query field or all listed string types. It also does not distinguish itself from sibling count tools like 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 use this tool versus alternatives. The description does not mention exclusions, preferred contexts, or sibling tools such as memory-key-count or hn-front-count, leaving an agent without enough information to select it confidently.

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