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

There are no annotations provided, so the description carries the behavioral disclosure burden. The statement 'The body is discarded' is a useful disclosure that the input is not stored or persisted. However, it does not explain what happens for invalid JSON or what result is returned, which is still relevant for a tool with no output schema.

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 short, front-loaded with the purpose, and contains no filler. The second sentence about discarding the body adds meaningful behavioral context. The only minor flaw is that 'body' could be more precise as 'JSON text' or 'the `json` parameter.'

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 low-complexity validator, the core purpose and side-effect behavior are covered, and the schema fills in parameter details. However, the description does not explicitly point the agent to the `json` parameter among the seven schema properties, and with no output schema it leaves the return-value behavior unstated. The description is adequate but not complete.

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 high coverage: all seven properties have descriptions, and the `json` parameter is explicitly described as 'JSON text to validate; discarded after the check.' The description itself adds no parameter-level meaning beyond this, so the baseline score of 3 applies.

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 verb and resource: 'Check whether a body is valid JSON.' This clearly identifies the core function and distinguishes it as a JSON-focused validator. It does not explicitly differentiate it from sibling validators like file-path-ok or domain-shape, and the term 'body' is slightly ambiguous, so it falls 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 this tool versus the many sibling validation tools. There are no usage conditions, exclusions, or alternative tool mentions. An agent must rely on the tool name and schema rather than the description to decide when validate-json is appropriate.

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