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

With no annotations, the description must carry the side-effect burden. It does state 'Query discarded,' which implies the input is not persisted, but this largely repeats the query parameter's schema description. It does not mention whether external calls occur, what happens when multiple parameters are supplied, or the output format.

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 short sentences with the core action front-loaded and no filler. Every phrase earns its place, even though the result is under-specified in other dimensions.

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?

Nine optional parameters, no required fields, no annotations, and no output schema make this complex, yet the description gives only two sentences. It fails to state which parameter to pass, whether at least one is required, or what the count applies to. The schema partially compensates, but an agent cannot confidently disambiguate the eight seemingly unrelated extra parameters.

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 adds no parameter-level meaning beyond labeling the input 'search query'; each parameter is already documented in the schema. It does not clarify that only 'query' is relevant while the other eight optional parameters are likely ignored.

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 uses a specific verb ('Count') and object ('characters in a search query'), so an agent can tell this is a length-counting utility rather than a validation or fetch tool. It is not a tautology of the name, but it does not explicitly clarify that only the 'query' parameter is counted despite the schema containing many unrelated optional fields.

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 about when to use this tool instead of a sibling like memory-key-count or normalize-url. The sentence 'Query discarded' describes a side effect, not a usage condition. An agent is left to infer that it should supply a search query, with no exclusions or alternatives.

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