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

With no annotations, the description must carry the full behavioral burden. It only notes that 'the body is discarded,' which is vague and does not clarify side effects, network access, or what happens with the other parameters. The schema mentions 'no disk access' for path, but that is in the schema, not the description.

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 a single sentence, which is concise, but it under-specifies. It lacks essential details about which parameter to use and what the output is. Being short is not the same as being well-structured; the sentence does not earn its place because it is too vague to be actionable.

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 9 parameters, none required, and no output schema. The description fails to explain the roles of the other parameters or how they relate to JSON validation. It is completely inadequate for an agent to understand the tool's full scope and invocation requirements.

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 tool description adds no additional meaning about parameters; it does not even reference the 'json' parameter. However, the schema itself provides adequate descriptions for each parameter, so the description does not need to compensate.

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 clear verb ('Check') and resource ('a body') but is ambiguous about which parameter holds the JSON. The 'body' is not mapped to the 'json' parameter explicitly, and the many unrelated parameters (ref, url, city, etc.) are not addressed, so the purpose is not fully distinct from other shape checkers.

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 on when to use this tool versus siblings like file-path-ok or domain-shape. The name implies JSON validation, but the description does not state the intended use case or conditions that would select it over alternatives.

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