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

With no annotations present, the description carries the full burden of explaining side effects and behavior. It only says values are discarded, but does not clarify whether the tool is read-only, what it returns, or how it handles invalid inputs.

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 concise and front-loaded—the core operation is stated in the first sentence, with a single additional clause about values. There is no redundancy or verbose structure.

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 description lacks essential context: it does not specify which input parameter contains the JSON object, what the return value looks like, how invalid inputs are handled, or whether the tool interacts with memory/storage. The presence of nine unrelated schema fields makes this omission critical.

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 descriptions appear copied from unrelated tools—URL normalization, weather hints, timezones, search length—and do not map to the stated operation of counting keys in a JSON object. No parameter is identified as the JSON object whose keys are counted, so the descriptions actively mislead rather than clarify.

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 operation—count keys in a JSON object and discard values—but the schema offers no obvious parameter that holds that object; the 'json' parameter is described as text to validate, not count. This leaves the actual input ambiguous despite the short purpose statement.

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 usage guidance is provided; there is no mention of when to prefer this tool over siblings like validate-json or when not to use it. The description does not frame the appropriate context.

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