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

With no annotations, the description must carry the full burden. The phrase 'Query discarded' does disclose a relevant behavioral trait, namely that the query is not retained after the call. However, it does not disclose whether all other supplied parameters are ignored, what the tool returns, or how it behaves when no query is provided, leaving meaningful gaps.

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 short and front-loaded. Both sentences contribute value, and there is no filler or redundant preamble. A score of 5 is not warranted only because the brevity also hides important operational details that the description would still need for a fully self-sufficient definition.

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 zero annotations, no output schema, and nine optional parameters with no explicit dependencies, this description is too thin to be fully actionable. It does not state that only `query` is used, what return type or shape to expect, or what happens when `query` is omitted, so a first-time agent cannot confidently plan the call.

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 high, so the rubric baseline is 3. The tool description itself does add a small signal that `query` is the meaningful input, but it does not clarify that the other eight optional parameters are likely irrelevant, nor does it explain the ambiguity created by having zero required parameters.

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 clearly states a verb and resource: count characters in a search query. It is easy to tell apart from sibling tools like validate-json or wiki-title-ok, but it does not explicitly disambiguate itself from other single-purpose counter/validators.

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 for when to choose this tool over siblings. There is no mention of when not to use it, what alternatives exist, or how to conditionally select it. The one-line description implies a narrow use case but does not help an agent decide between this and other check/count tools.

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