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

The description adds the behavioral detail that values are discarded, which is useful beyond the input schema. However, with no annotations provided, it does not disclose return format, side effects, or whether any state is modified, leaving the description to carry more weight than it can with one short sentence.

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 very concise and front-loaded, with no wasted sentences. It briefly loses value by omitting important usage and parameter mapping details, but as a concise statement, it is clean and direct.

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 lack of annotations, absence of an output schema, and a large parameter set with no clear indication of which parameter to pass, the description is not complete enough for an agent to invoke the tool confidently. The connection between 'Count keys in a JSON object' and the specific parameters is missing.

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 coverage is 100%, so the schema already documents each parameter. The description does not clarify which parameter contains the JSON object to count, despite the schema listing nine unrelated-looking optional parameters. It adds no meaning beyond what the parameter descriptions already provide.

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 tool's action: count keys in a JSON object, and notes that values are discarded. This is specific and understandable, though it does not explicitly distinguish the tool from similar JSON-related siblings like validate-json.

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 alternatives such as validate-json, domain-shape, or normalize-url. The description implies a use case for counting keys but gives no conditions, exclusions, or references to sibling tools.

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