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

With no annotations and only a two-sentence description, the tool does not disclose return values, error behavior, side effects, or edge cases. 'Values discarded' hints at behavior but leaves almost everything unspecified.

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 extremely short and easy to read, but it omits essential information. It is concise to the point of being unhelpful rather than efficiently informative.

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?

The tool has nine parameters, no output schema, no annotations, and a minimal description. The description does not explain what the parameters do, what output is produced, or how the tool fits into a workflow. It is far from complete.

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 schema description, the descriptions appear unrelated to the stated purpose of counting keys in a JSON object. For example, 'json' is described as 'JSON text to validate; discarded after the check', which suggests validation, not key counting. The parameter semantics are confusing and inconsistent.

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 does not explain how this relates to the many unrelated parameters or distinguish it from sibling tools like validate-json or search-query-len.

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 provided about when to use this tool versus alternatives, when not to use it, or what kind of input is expected. The description gives no practical usage context.

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