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

No annotations are provided, so the description must carry the full behavioral burden. It discloses one trait: 'Values discarded.' But it does not mention side effects, required permissions, whether it is read-only, or what the return value looks like. The parameter schema hints at 'no disk access' and 'discarded after the check,' but these are not in the description itself. The disclosure is minimal and incomplete for a tool with 9 parameters.

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 a single concise sentence with no wasted words. It is front-loaded with the core action. While it could benefit from more detail, it does not suffer from verbosity. It earns a solid score for conciseness.

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 9 parameters, no output schema, and no annotations, a one-sentence description is grossly inadequate. It does not explain how to invoke the tool, which parameters are required (none are), what the output format is, or any constraints. The description is essentially useless for an agent attempting to use it correctly, especially given the bizarre parameter list.

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. However, the parameter descriptions are confusing and appear copied from unrelated tools (e.g., 'Git ref name; discarded after the shape check,' 'City name for a public weather hint'). They do not explain how each parameter contributes to counting keys in a JSON object. This actively misleads rather than clarifies, so a score below baseline is warranted.

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.' It identifies the resource (JSON object) and the operation (count keys). It does not explicitly differentiate from siblings, but no sibling performs key counting. However, the 9 unrelated parameters create ambiguity about which parameter carries the JSON object, slightly diminishing clarity.

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?

The description gives no guidance on when to use this tool versus alternatives. It does not mention any preconditions, alternatives, or exclusions. With a single sentence and no usage context, an agent has no way to decide when this tool is appropriate over, say, validate-json or search-query-len.

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