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

The phrase 'Values discarded' gives some behavioral hint, but the description does not explain the return format, error handling for invalid JSON, or whether inputs are consumed. With no annotations available, this is insufficient.

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 brief and front-loaded, but it is too sparse to be useful. It omits the critical mapping between the tool's purpose and the provided parameters.

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 lacks an output schema and the description does not state what is returned, how the JSON object should be supplied, or what errors can occur. The presence of 9 optional unrelated parameters compounds the incompleteness.

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 the schema describes each parameter, those descriptions are unrelated to counting keys in a JSON object. The 'json' parameter is described as validation/discard, not key counting, and the other parameters appear to be copied from unrelated tools.

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 the action ('Count keys in a JSON object') but does not identify which input parameter contains the JSON object. The 9 unrelated string parameters make the intended purpose ambiguous.

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 about when to use this tool versus sibling tools such as validate-json, search-query-len, or other checking tools. There is no indication of appropriate or inappropriate use cases.

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