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

With no annotations, the description carries full responsibility for behavioral disclosure. It only states that 'the body is discarded,' which is a small transparency note, but it fails to indicate whether the operation is read-only, what happens to the other parameters, or whether any output is returned. This is insufficient for a tool with no annotation coverage.

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 is under-specified. It omits critical information about the tool's scope and parameters, making it more of a placeholder than a well-structured description. It is not appropriately sized given the tool's complexity.

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 and no output schema, yet the description only mentions JSON validation. It fails to explain the relevance of parameters like city, zone, url, etc., which suggests a broader validation role. This incompleteness could mislead an agent into thinking the tool only checks JSON when it likely handles multiple shapes. The description is not complete enough for the tool's complexity.

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 each parameter already has a description. The tool description adds no extra meaning and does not clarify which parameter corresponds to 'a body' (likely 'json'), nor does it explain the purpose of the many other parameters. Baseline 3 is appropriate since the schema does the heavy lifting.

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 ('Check') and resource ('whether a body is valid JSON'), which clearly indicates the core function. However, it does not differentiate from sibling shape-validator tools (e.g., domain-shape, github-repo-shape) which also validate specific formats, and the presence of 8 unrelated parameters suggests the description may be narrower than the actual tool behavior.

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 on when to use this tool versus alternatives. The description does not mention any conditions, exclusions, or scenarios, leaving the agent to infer usage from the name and schema alone.

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