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

No annotations are provided, so the description carries the transparency burden. It mentions that values are discarded and some parameter descriptions note 'discarded' or 'no disk access', but it does not disclose return behavior, errors, or whether any state is modified.

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 concise and front-loaded, with no unnecessary wording. The parameter descriptions are also short and direct, keeping the overall definition compact.

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 the complexity of nine optional parameters and no output schema or annotations, the description is not fully complete. It lacks explicit instructions on which parameter to provide and what the result will look like.

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?

Although every parameter has a description, the descriptions are misaligned with the tool purpose (e.g., 'json' is described as 'JSON text to validate; discarded after the check' rather than as the object whose keys are counted). With nine optional parameters and no required fields, the input mapping is ambiguous.

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 the action: count keys in a JSON object and ignore values. It is specific enough to distinguish from sibling tools like validate-json, though it does not explicitly name which parameter carries the JSON object.

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 compared with alternatives such as validate-json or search-query-len. The intended use is only implied by the one-sentence description.

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