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

No annotations are provided, so the description carries the full burden. It does disclose a useful behavioral trait: 'The body is discarded,' meaning the input is not retained. However, it omits how the validity result is reported, error behavior, and any authentication or rate-limit context.

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 no padding, and the core purpose is front-loaded. Both sentences earn their place: one states the function, the other adds the behavioral note about discarding input.

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?

Although the tool is conceptually simple, the definition is not self-sufficient: it does not clarify which parameter is the 'body', how the validity check is returned (there is no output schema), or what happens on invalid JSON. The unrelated url/host/zone parameters compound the ambiguity.

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 coverage is 100%, which normally warrants a baseline of 3, but the schema is clearly contaminated: url, host, and zone are described as 'HTTPS URL to normalize or cite', 'Public hostname', and 'IANA timezone name' — all unrelated to JSON validation. The description's 'body' also fails to map cleanly to the json parameter, creating real confusion about what to supply.

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 verb and resource: 'Check whether a body is valid JSON.' The tool name reinforces this intent. However, it refers to a 'body' while the schema contains no parameter named 'body', and with no sibling tools listed it does nothing to differentiate from alternatives.

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 implies the usage scenario — validate a JSON body — but offers no explicit guidance on when to use it, no exclusions, and no alternatives. With only one sentence of guidance and no sibling context, the agent is left to infer applicability.

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