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

The description mentions 'The body is discarded,' which indicates no persistence of input. However, it fails to disclose that only the 'json' parameter is actually used and that all other parameters (ref, url, city, etc.) are ignored. This is a significant behavioral omission that could mislead an agent into thinking multiple inputs affect validation. The given schema descriptions for those other parameters are also misleading, but the tool description does nothing to clarify the actual 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, consisting of two short sentences. It is well-structured, front-loading the primary action and then noting the disposal side-effect. There is no superfluous text or repetition, making it efficient for an agent to parse quickly.

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 the tool has 9 parameters, none required, and only one relevant ('json'), the description is severely incomplete. It does not explain that the other parameters are irrelevant or ignored, nor does it clarify how the input is passed (e.g., as a string). Without that context, an agent could incorrectly assume all parameters contribute to validation. The description leaves too much essential usage context unaddressed.

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 description does not add any meaningful clarification over the schema. In fact, it introduces ambiguity by referring to a 'body' parameter that does not exist in the schema. The schema descriptions for the unrelated parameters (e.g., 'ref' as 'Git ref name; discarded after the shape check') are clearly generic and not tailored to this tool, and the description fails to correct that. Only the 'json' parameter description hints at relevance, but the tool description does not highlight it. Overall, the parameter semantics are poorly conveyed.

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 the tool's core function: to check whether a given input is valid JSON. The verb 'check' and the object 'JSON' provide a specific and unambiguous purpose, and the tool name reinforces this. Although the term 'body' is imprecise, it does not obscure the main intent.

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 usage (you would call this when needing to validate JSON) but does not explicitly state when to use it or contrast it with other tools. There is no guidance on selecting this over a sibling tool, though the specialized name partially compensates. The lack of explicit 'use this when' or 'not for' instructions keeps this at a mid-range score.

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