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

With no annotations present, the description carries the full burden. It does disclose that the body is discarded, which informs the agent about data retention. However, it does not describe what happens with invalid JSON, whether errors are returned, or how the result is communicated. This leaves significant behavioral ambiguity.

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 appropriately brief: two short sentences with no wasted words. The core purpose is front-loaded, and the discarding behavior is a meaningful additional detail. It is concise without being tautological.

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 has a complex schema with many optional fields that the description does not address, and there is no output schema to clarify return behavior. The description hints at validation but does not explain how the 'body' relates to the 'json' parameter or what the caller should expect. This is incomplete for a tool with such ambiguity.

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 already provides descriptions for every parameter (coverage is high), so the baseline is 3. The description adds no additional per-parameter meaning and does not clarify why many seemingly unrelated properties (ref, url, city, feed, host, path) appear in the schema. It adds minimal value beyond 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 clearly states the tool's primary action: 'Check whether a body is valid JSON.' This is a specific verb+resource pairing that is easily distinguished by name. However, it does not explicitly differentiate from sibling shape-checking tools, though the JSON validation focus is obvious.

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 alternatives. The description neither mentions when it is appropriate nor names any alternatives. The 'body is discarded' note implies a side-effect-free check, but there is no explicit context for choosing this tool over similar validation tools.

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