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

The description discloses one behavioral trait: 'The body is discarded.' This is useful because it indicates the tool is stateless and does not retain inputs. However, with no annotations available, the description carries the full burden of behavioral disclosure; it does not mention what the tool returns on valid versus invalid JSON, any error behavior, or side effects beyond discarding the input.

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 purpose is front-loaded, and the second sentence adds a meaningful behavioral note about data handling. Every word earns its place, making this an exemplary model of concise tool documentation.

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?

For a tool with no annotations and no output schema, the description is too sparse. It does not explain the expected return value (e.g., boolean, success/failure), how to provide the JSON body (which parameter), or when to choose this tool over other validation siblings. The schema contains extraneous parameters like 'url' and 'city' that could confuse an agent, and the description does nothing to resolve that ambiguity.

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 schema provides descriptions for all parameters, including 'json: JSON text to validate; discarded after the check', so schema coverage is high (100%). The description itself adds no additional parameter semantics and does not clarify which parameter is the primary one, leaving the agent to rely on the schema. Thus, the baseline score of 3 is appropriate.

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 and resource: 'Check whether a body is valid JSON.' This clearly signals the tool's purpose and differentiates it from siblings like file-path-ok or url-ok, which validate other resource types. However, it does not explicitly mention the 'json' parameter or clarify what 'body' means in the context of an API call, so the purpose is clear but not fully specified.

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 provides no guidance on when to use this tool versus alternatives. There is no mention of conditions, exclusions, or references to sibling tools such as file-path-ok or url-ok. An agent must infer usage solely from the tool name and description, which is insufficient for deciding between similar validation tools.

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