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

No annotations are present, so the description carries the full disclosure burden. It adds one behavioral note—'The body is discarded'—but this repeats the json property description and does not mention the return value, error behavior, or whether the other parameters are ignored or processed.

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?

With two short sentences, the description is front-loaded and contains no wasted words. It is sparse, but it is not the place where the tool's information is missing.

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?

A nine-parameter tool with no annotations and no output schema needs more than a two-sentence description. The description does not state which parameter is 'the body,' what the validation returns, or why unrelated parameters like city and zone are part of the schema.

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%, and the schema already describes all nine parameters individually. The description loosely maps 'body' to the json parameter but provides no additional meaning for the remaining eight optional parameters, which a caller might expect to be relevant.

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 says it 'checks whether a body is valid JSON,' which is a specific verb (check) on a specific resource (JSON body) and is distinct from the other shape/check siblings like browser-url-ok or wiki-title-ok. The term 'body' is slightly ambiguous—it could mean the json parameter or some other request body—so it stops short of a perfect 5.

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?

There is no guidance about when to use validate-json instead of alternatives and no exclusions or sibling references. The schema exposes nine parameters (e.g., url, city, zone, query) but the description does not explain whether any of these are relevant to the validation operation or when only the json parameter should be supplied.

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