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

With no annotations, the description carries the burden of behavioral disclosure. It adds a useful note that the body is discarded, implying no retention or side effects, but it does not disclose the return value, error behavior, or what happens on invalid JSON.

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 a single front-loaded sentence with no filler. Every clause adds information: what it does and what happens to the 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?

The tool has no annotations or output schema, yet the description does not explain the result format or error handling. Given the schema exposes many unrelated-looking fields, the sparse description leaves an agent uncertain how to interpret the tool's response and which parameter is essential.

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 has rich per-property descriptions, so schema coverage is high and the description need not repeat parameter details. The description adds no guidance about which parameter is the 'body,' but the `json` property already says 'JSON text to validate; discarded after the check.'

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 a specific action ('Check whether a body is valid JSON') and is distinguishable from sibling shape validators by focusing on JSON syntax. The term 'body' is slightly ambiguous and doesn't explicitly tie to the `json` parameter, but the core purpose is unmistakable.

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 on when to choose this tool over alternatives such as `domain-shape`, `file-path-ok`, or `normalize-url`. It implies JSON validation is the use case but does not state exclusions, prerequisites, or alternatives.

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