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

The description's only behavioral disclosure, 'The body is discarded,' adds a relevant side-effect note, but it duplicates the json parameter description in the input schema ('discarded after the check'). With no annotations and no output schema, the description still fails to disclose what the tool returns, whether validation errors are surfaced, or any other runtime behavior.

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 purpose appears in the first sentence, and the secondary side-effect statement is short. There is no filler or unnecessary elaboration.

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?

With no output schema and no annotations, the description should explain what a successful or failed validation returns, but it does not. It also never clarifies how the 'body' maps to the json parameter or why url/host/zone are present, leaving important context missing for a tool an agent must invoke correctly.

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 parameters are already well documented. The tool description adds no further meaning to url, host, json, or zone beyond what the schema provides, so the baseline score of 3 is appropriate.

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 clearly states a specific action ('Check') and resource ('a body is valid JSON'), so an agent can immediately tell what the tool does. It does not explicitly differentiate from sibling tools by name, but siblings like normalize-url, status-catalog, and timezone are clearly distinct in purpose.

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?

Usage context is implied by the phrasing 'Check whether a body is valid JSON' – an agent can infer it should be used when validation is needed. However, the description does not explicitly state when to use it versus alternatives, nor does it mention any conditions or exclusions.

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