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

The description claims values are discarded, but the parameter descriptions (e.g., 'JSON text to validate; discarded after the check') suggest validation rather than counting. There is no disclosure of side effects, and the parameter descriptions contradict the stated purpose.

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 a single concise sentence, but it fails to address the complexity of the parameter set or explain how they relate to the purpose. The structure is too minimal for the tool's apparent scope.

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?

With 9 parameters and no output schema, the description provides no context on expected input format, output, or how the parameters contribute to the key-counting operation. The tool is not contextualized for an agent to use correctly.

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?

The schema covers all 9 parameters, but the descriptions are inconsistent with the tool's purpose. For example, 'json' is described as 'validate', not 'count keys'. The parameter descriptions do not add meaningful guidance for using the tool as described.

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 states a clear action ('Count keys in a JSON object'), but the parameter list contains a mix of unrelated fields (e.g., 'url', 'city', 'host') with no obvious mapping to the JSON object input. This makes the actual purpose ambiguous in practice.

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 on when to use this tool versus siblings like 'validate-json' or other counting/checking tools. The parameter descriptions do not clarify the intended use case.

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