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

With no annotations, the description carries the transparency burden; 'Query discarded' is a useful disclosure that the input is not retained. But it does not state the return value, whether any network or side effects occur, or what happens if the query is empty.

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 two sentences are efficient and front-loaded, but the definition is under-specified for a 9-parameter tool with no output schema. It sacrifices necessary invocation guidance for brevity.

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?

There is no output schema and no mention of the return format or which parameter to pass among the nine optional fields. The description is not complete enough for an agent to confidently invoke this tool correctly, especially given the unrelated parameter descriptions.

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 tool description adds little beyond referring to a 'search query.' The schema's `query` description ('Search text; discarded after the length check') actually provides the key semantics, though the description does not clarify why the other eight parameters are accepted.

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 begins with a specific verb and object: 'Count characters in a search query,' which states the core function clearly. However, it does not differentiate this from sibling count/shape tools or explain why the schema exposes nine unrelated optional parameters, so it stops short of full clarity.

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 when-to-use guidance, conditions, or alternatives are provided. The description does not tell the agent that only the `query` parameter is relevant or that the other accepted parameters (url, json, path, etc.) should be ignored for this tool.

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