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 discloses that the body is discarded (a useful non-persistence trait, reinforced by the schema param descriptions), but says nothing about behavior on invalid JSON, error responses, or return format. For an unannotated tool this is a thin disclosure.

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 sentences, zero filler, and the core purpose is front-loaded. However, at this length it borders on under-specification rather than disciplined conciseness, especially given the odd collection of nine unrelated parameters.

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?

The tool has 9 parameters, none required, no output schema, and no annotations, and the description does not explain why params like city, zone, and query are present or which one constitutes the 'body'. A checker with this much surface area needs more guidance to be safely invoked.

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 baseline 3 applies. The description itself adds nothing about parameters beyond what the schema already provides, and the term 'body' introduces mild ambiguity versus the 'json' parameter. The schema's own per-param notes (e.g., 'discarded after the check') carry the semantic weight.

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?

States a specific verb and resource ('Check whether a body is valid JSON') and discloses that the body is discarded. It conveys the core function clearly, though 'body' doesn't map unambiguously to the 'json' parameter in the schema, and it doesn't differentiate from the many sibling shape-check tools (file-path-ok, github-repo-shape, etc.).

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?

No when-to-use guidance, no exclusions, and no mention of alternatives. With 28 sibling tools that follow the same shape-check pattern, there is nothing helping the agent decide between validate-json and tools like file-path-ok or domain-shape.

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