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

The description discloses a non-obvious behavior: 'The body is discarded', implying no retention. It also frames the operation as a check, which is useful because no annotations are present. However, it does not explain return values, error behavior, or what happens with invalid JSON, so the behavioral coverage is partial.

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 brief, purposeful sentences with no redundant filler. The core validation purpose is front-loaded, and the disposal side effect is stated efficiently.

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 a seven-parameter schema, the description does not map 'body' to the 'json' parameter or clarify what a caller should pass. Without an output schema, it also omits the response format for valid versus invalid JSON. The description is too sparse to be complete for this tool's complexity.

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 already documents every parameter, including 'json' as the JSON text to validate, so the description adds little semantic value. The term 'body' in the description is ambiguous relative to the schema's parameter names and requires inference. Baseline 3 applies because the schema carries most of the parameter-semantic load.

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 validation action: 'Check whether a body is valid JSON' and clarifies the body is discarded. It clearly identifies the resource being validated and is not a tautology. It does not explicitly differentiate from sibling shape-checking tools, so it stops short of a 5.

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 guidance is given about when to use validate-json versus sibling tools like domain-shape or file-path-ok. It does not state conditions, exclusions, alternatives, or when not to use this tool. The only usage cue is implicit in the tool's name and description.

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