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

Because no annotations are provided, the description carries the full behavioral burden. It does disclose that the query is discarded and that the operation is a character count, but it omits the return shape, encoding or edge-case behavior, and what happens with the other eight accepted parameters. Thus it gives partial transparency.

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 most important action is front-loaded in the first sentence. 'Query discarded' is a separate, useful behavioral note that earns its place.

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 nine optional parameters, no output schema, and no annotations, a one-line description leaves too much unspecified: return value, how the extra fields relate to the tool, and edge cases such as empty input. The schema documents each property, but the description does not connect them to the tool's purpose, making agent-side reasoning incomplete.

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 the baseline is 3 even without parameter information in the description. The description emphasizes 'search query' as the relevant input, but it never names the 'query' property explicitly or explains the other eight string parameters, which remain optional in the schema. It adds only marginal meaning beyond 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 phrase 'Count characters in a search query' names a specific verb and resource, and 'Query discarded' adds a side-effect note. However, it does not contrast with related sibling tools or clarify which schema field is the query, so it stops short of full differentiation.

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 statement about when to prefer this tool over the many sibling count/check tools, and no exclusions or alternatives are named. The only implied context is the tool name, so an agent gets no routing guidance.

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