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

With no annotations provided, the description carries the full burden of behavioral disclosure. It mentions that the body is discarded (a useful privacy note), but it does not disclose the return value for valid/invalid JSON, error handling, or what happens with the other schema parameters. This is insufficient for a validation tool.

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 very concise and front-loaded with the core action, and the discarding note is relevant behavioral context. However, it is almost terse to a fault, leaving out important operational details. Still, every sentence has purpose, so it earns a 4.

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?

Without annotations or an output schema, the description must be self-sufficient. It fails to explain the return value, which parameter to pass the JSON in, or why the schema includes unrelated fields like 'city' and 'feed'. An agent would struggle to correctly invoke this tool based on this description alone.

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 already provides descriptive text for all parameters, including 'json': 'JSON text to validate; discarded after the check', so schema coverage is high. The description does not add extra parameter meaning or clarify which field is the 'body'. Baseline 3 is appropriate because the schema does the documentation work.

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 action ('Check whether a body is valid JSON') and identifies the resource (JSON body). It is clear enough to distinguish from sibling shape-check tools like file-path-ok or browser-url-ok, though 'body' is slightly ambiguous and the tool doesn't explicitly differentiate itself from alternatives.

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 other validation tools, no exclusions, and no context about typical use cases. It simply restates the function without pointing to alternatives or prerequisites.

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