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

With no annotations, the description must carry the transparency burden. 'Query discarded' is a useful side-effect/privacy disclosure, and counting is read-only by implication, but the description says nothing about whether the other eight parameters are ignored or about the result's nature. It is minimally transparent but not contradictory.

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?

Two short sentences front-load the core action and add only one extra behavioral note, so there is no filler. It is concise, though the brevity comes at the cost of missing usage and return details.

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?

For a simple length-counting tool the description and the query parameter's schema entry are arguably enough to attempt a call, but the definition does not explicitly state the output format or that only 'query' should be supplied, and the 0-required-parameters schema leaves ambiguity when called with no arguments. The gap is noticeable but not fatal for a read-only counter.

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 description adds no parameter semantics beyond the schema. The schema already describes 'query' as 'Search text; discarded after the length check', which matches the tool description, so no further parameter guidance is provided by the description.

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 names a specific action ('Count characters') and a clear object ('a search query'), so an agent can tell this is a length-measurement tool. It does not explicitly distinguish itself from sibling count/check tools, but the action and the 'query' resource are specific enough.

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 when-to-use guidance, no mention of which parameter to populate, and no alternatives or exclusions. With all nine parameters optional, the agent must infer from the schema that 'query' is the intended input.

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