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

No annotations are provided, so the description carries the full behavioral burden. It does disclose the notable behavior 'Query discarded,' which indicates input is not retained. However, it does not explain whether the operation is side-effect-free, whether all other schema fields are ignored, or what happens when multiple fields are supplied, leaving an incomplete behavioral picture.

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 concise sentences, with the main purpose first and the behavioral caveat second. Every word earns its place and there is no redundant filler.

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?

Given nine optional string parameters, no output schema, and no annotations, the description is too sparse. An agent cannot confidently determine that `query` is the parameter to populate, what the tool returns, or why the other fields exist. A more complete definition would explicitly name `query` and state that all other inputs are ignored or discarded.

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 mostly restates what the `query` parameter already says in the schema ('Search text; discarded after the length check') without adding clarity about which parameter to use, parameter precedence, or the meaning of the other eight properties.

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 operation ('Count characters in a search query') and the name reinforces the resource being measured. It is not a tautology and is specific enough to distinguish the core action, but it does not explicitly differentiate itself from similarly named sibling counting tools such as memory-key-count, and it leaves open which of the nine schema fields is the intended 'search query'.

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 like normalize-url, validate-json, or fetch-status. The description only says what the tool does, not when it should be selected or when a different tool would be more appropriate.

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