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

With no annotations, the description takes the full burden of explaining behavior. It does disclose that values are discarded, which is a useful trait, but it does not state what is returned, whether invalid input raises errors, or that the JSON object being counted is the set of provided arguments. This is a major gap for a tool with no other behavioral metadata.

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: two short sentences with no waste. 'Values are discarded' is a useful behavioral note. It is appropriately sized for a straightforward utility tool, though the content could be improved without bloating.

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?

Given 9 parameters, no output schema, and no annotations, this is incomplete. The description does not explain what the input 'JSON object' refers to (e.g., the set of input properties) or what the count is used for, forcing an agent to infer too much for a reliable selection and invocation.

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 100% of parameters with detailed descriptions, so the description need not repeat them. The description adds no per-parameter meaning beyond the schema, which aligns with the baseline of 3 for high coverage. Nothing about the 'JSON object' mapping to the parameters is clarified.

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 tool counts keys in a JSON object, which is a specific verb and resource. It is clear but does not distinguish itself from sibling tools (e.g., state that it operates on the memory/input object or contrast with validate-json), so it does not reach the highest tier.

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 instead of alternatives. The description only defines the function, leaving the selection context completely unspecified. There are no explicit conditions, exclusions, or mentions of sibling tools.

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