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

With no annotations, the description carries the full burden. It only states that the body is discarded, but does not disclose return values, error behavior, or whether any state changes occur. The agent is left wondering what the tool actually returns (e.g., boolean, success/failure) and what side effects exist.

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: two short sentences with no filler. The core action is front-loaded, and the extra note about discarding the body is useful and non-redundant. 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?

The tool has 9 optional parameters and no output schema, yet the description gives no guidance on how the parameters should be used for validation. The presence of unrelated parameters like 'city', 'zone', and 'ref' is unexplained. The description is insufficient for an agent to confidently construct a correct invocation.

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 provides 100% coverage with each parameter described. The tool description adds no additional meaning to the parameters, but since the schema already documents them, a baseline score of 3 is appropriate. The description does not need to repeat schema info.

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.' This distinguishes it from sibling validation tools like file-path-ok or browser-url-ok, which target different input types. The action is unambiguous and focused.

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 use this tool versus alternatives. It does not mention any conditions, prerequisites, or scenarios where this tool is preferred over other validators. There is no 'use when' or 'use instead' guidance.

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