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

With no annotations provided, the description carries the full burden of explaining behavior. It does disclose that the body is discarded, which implies no persistence, but it does not state whether the tool returns a boolean, throws an error, handles malformed input, or what 'valid JSON' means in terms of schema strictness.

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 concise and front-loaded, with no filler or redundant wording. The single sentence is easy to parse, though it sacrifices important detail for brevity.

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 is incomplete in context: there is no output schema, no annotations, no required parameters, and no explanation of the return value or error semantics. The mismatch between 'body' in the description and the diverse optional schema properties leaves significant gaps for an agent trying to invoke it correctly.

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 properties have individual descriptions and 100% coverage, but most are irrelevant to JSON validation (e.g., 'url', 'city', 'feed', 'zone', 'query'). The 'json' property is the only clearly relevant one, yet the description says 'body' rather than mapping to that parameter, leaving the agent to guess which properties actually matter.

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 the core action—'Check whether a body is valid JSON'—with a specific verb and resource, so the general purpose is clear. However, it refers to 'body' while the input schema exposes a 'json' property, creating ambiguity about what exactly should be passed.

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 instead of the many sibling tools, nor does it mention any prerequisites or typical usage. It only states what it checks, with no context about when validation is appropriate or what alternatives might apply.

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