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

No annotations exist, so the description carries the full transparency burden. It says 'Query discarded,' but that phrase is already in the schema's `query` description, so it adds little beyond the structured text. It does not disclose return format, error behavior, or the effect of passing multiple parameters.

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, zero filler, and the core action is front-loaded. The second sentence adds a useful behavioral note about discarding. Economical and well-structured.

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 has 9 optional parameters and no output schema. The description does not state which parameter supplies the search query, what output the caller receives, or how to handle the absence of all parameters. Even with rich schema lines, an agent could not be confident it is calling the tool correctly from the tool 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 reported at 100%, so the baseline is 3 even without parameter detail in the description. The description neither adds nor removes parameter semantics, merely referring generically to 'a search query' while the actual parameter is clearly named `query` in the schema.

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 clear verb ('Count characters') and a specific resource ('a search query'), so the core action is unambiguous. It does not explicitly differentiate from sibling tools such as 'memory-key-count' or 'hn-front-count', so it stops short of a 5.

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 about when to use this tool versus siblings, which parameter should be provided, or whether parameters are mutually exclusive versus combinable. With 9 optional parameters and no required field, the agent is left without usage direction.

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