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

With no annotations, the description carries the burden. It discloses that the body is discarded (implying no side effects), but it does not describe the return format (e.g., boolean, error) or any strictness rules. This is minimal but not misleading.

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 sentences with no filler. The primary action is front-loaded, and the discard behavior is mentioned succinctly. Perfectly sized for a simple validation tool.

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 description is missing the expected output (e.g., returns true/false) and does not clarify whether other parameters (url, host, zone) are ignored or relevant. While the tool is simple, an agent might be uncertain about the return value and parameter usage. The schema covers parameter names but not usage context.

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?

Schema description coverage is 100%, so the baseline is 3. The description adds little beyond the schema: it uses 'body' to refer to the JSON text, which is already described in the 'json' parameter. No new semantic insight is provided.

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 clearly states the action ('Check whether a body is valid JSON') with a specific verb and resource. It is distinct from all siblings, which focus on URLs, zones, and other formats. The term 'body' is slightly ambiguous but likely refers to the 'json' parameter, and the tool name reinforces the purpose.

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 provided on when to use this tool versus alternatives. While it is clearly distinct from siblings, there is no mention of scenarios (e.g., validating user input before processing) or exclusions. The description does not help the agent decide if this is the right tool.

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