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

With no annotations provided, the description must carry the full burden of behavioral disclosure. It does disclose that the body is discarded, which is a notable side effect. However, it does not state what the tool returns (e.g., a boolean, an error), whether it throws on invalid JSON, or how it handles edge cases. This is a gap for a validation tool, but the main behavior is at least partially transparent.

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 extremely concise—two short sentences—with the primary action front-loaded. Every word earns its place, and there is no fluff or repetition. It is a model of brevity.

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?

Given that there is no output schema, the description should explain what the tool returns, but it does not. It also lacks any usage guidelines or context about when to invoke it. While the schema fully documents parameters, the absence of return-value information and usage guidance makes the definition only minimally complete for an agent to confidently call it.

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 has 100% coverage, with each of the 9 parameters having a description. The tool description itself adds no parameter-specific information beyond the generic 'body', relying entirely on the schema. Since the schema fully documents each parameter, the baseline of 3 is appropriate; the description does not need to compensate for missing schema details.

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 a clear resource ('a body is valid JSON'). It is unambiguous and distinguishes itself from sibling tools, none of which perform JSON validation. The mention that the body is discarded adds a precise side effect, making the purpose even clearer.

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?

The description provides no guidance on when to use this tool versus alternatives, nor does it mention any prerequisites or context. While no sibling tool performs the same function, the description does not explicitly state when an agent should select it, such as 'Use when you need to verify a JSON string before parsing.' The purpose is clear but the usage context is left entirely to inference.

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