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

With no annotations provided, the description carries the full burden. It does disclose that the body is 'discarded,' which is a meaningful non-retention trait. However, it doesn't state the return type (boolean) or error behavior, so the disclosure 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?

Two short sentences with zero filler; the core behavior is front-loaded and the discard notification follows naturally. 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?

For a simple validation tool, the description is adequate, but it leaves two gaps: it doesn't clarify that only the 'json' parameter is relevant (the other three optional fields are distractors), and it doesn't specify the result shape. That's acceptable for a minimal check but not rich enough to be called 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 schema already describes all four parameters (100% coverage), so the baseline is met. The description adds nothing about how 'url', 'host', or 'zone' relate to validation; it only refers generically to 'body,' leaving the json parameter's role to the schema.

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 maps directly to the tool name and differentiates it from the URL/timezone siblings, since it is explicitly about JSON syntax validation rather than normalization or citation.

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 offered about when to call this tool versus an alternative—for example, a schema validator or a JSON parsing tool. The description states what it does but not when it is the right choice or when it would be inappropriate, leaving the agent to infer usage.

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