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

There are no annotations, so the description carries the burden of behavioral disclosure. It does add one meaningful behavioral trait: the body is discarded, implying a stateless, side-effect-free check. But it does not state the result format (boolean vs error), whether only the 'json' parameter is considered, or what happens for malformed JSON beyond 'invalid'.

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 two short sentences with no filler. The core validation action is front-loaded, and the discard behavior is added in a single follow-up sentence. Every word earns its place.

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?

Despite the apparently simple core action, the tool has seven string parameters with no required markers, no output schema, and no mention of what the caller should expect back. The description also never identifies which schema parameter is 'the body', so an agent cannot confidently know what to pass or what result is returned.

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 input schema already provides descriptions for all seven parameters, including 'json' described as 'JSON text to validate', so schema coverage is high and the baseline is 3. The tool description adds no additional parameter meaning and even obscures the mapping by referring to a generic 'body' rather than the 'json' field.

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 specific action ('Check whether') and a resource ('a body is valid JSON'), which clearly distinguishes it from the other shape/ok validators in the sibling list. However, the term 'body' is not explicitly mapped to the 'json' parameter in the schema, so there is slight ambiguity about which input is the actual JSON payload.

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 gives no guidance about when to use this tool versus any of the many validation-focused siblings such as domain-shape, file-path-ok, or browser-url-ok. There are no explicit when-to-use, when-not-to-use, or alternative tool references, leaving the agent to infer usage solely from the name.

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