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

With no annotations, the description carries the full burden for behavior, but the only trait disclosed is that values are discarded. It omits whether nested keys are counted, what happens on invalid JSON, and what the tool returns, leaving important behavior implicit.

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?

Two short sentences with action first and no filler. The values-discarded note adds real information, so every word earns its place.

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?

For a tool with nine optional parameters, no annotations, and no output schema, this description is too sparse. It does not state the meaningful input parameter, the depth of key counting, error behavior, or how this tool relates to validate-json.

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 description coverage is 100%, so the baseline is 3 despite the description adding no parameter-level detail. However, the description does not confirm that the JSON object is supplied through the `json` parameter, and the schema's own `json` description says 'to validate', so the mapping is not fully disambiguated.

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 names a specific operation (count), a specific resource (keys in a JSON object), and adds a relevant qualifier (values discarded). It is distinguishable from validate-json, though it does not explicitly call out that distinction or define key depth.

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 prefer this tool over validate-json or the sibling shape/ok tools, and no prerequisites such as valid JSON or which input to use. The intended use is only implied by the verb itself.

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