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

With no annotations, the description carries full behavioral burden. It discloses that the query is discarded, but does not explain behavior for the other parameters, the return value, or side effects. The schema descriptions mention discarding for each parameter, but the tool description only covers the query.

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 sentence, which is concise, but it is too sparse to be helpful. It lacks essential details such as which parameter to use and what the output is, so the brevity works against it.

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, yet the description does not explain the return format, which parameter is relevant, or how to handle the extraneous fields. An agent would struggle to call this correctly without additional inference.

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% with each parameter having a description, so the baseline is 3. The tool description adds no extra meaning beyond what the schema already provides; it does not clarify which parameter is the primary input or how the others relate to the described action.

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 action 'Count characters in a search query' with a specific resource, but the schema exposes 9 unrelated parameters (ref, url, city, etc.) that are not mentioned in the description, creating ambiguity about whether the tool accepts any of these or only 'query'. It does not distinguish itself from siblings 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?

No guidance is given on when to use this tool versus alternatives such as memory-key-count or calc-eval. The description does not specify that this is only for search query strings or that other tools should be used for other input types.

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