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

With no annotations provided, the description carries the burden of behavioral disclosure. It adds one useful behavioral fact—'The body is discarded'—which clarifies that the tool has no persistent side effect. However, it does not describe what the tool returns (e.g., true/false, validation report) or clarify that only the 'json' parameter is relevant while 'url', 'host', and 'zone' are likely ignored.

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?

Two short sentences, front-loaded with the core purpose and no filler. Every word earns its place, and the discard note is an efficient addition.

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?

For a tool with no output schema and no annotations, this description is incomplete. It fails to specify that three of the four schema parameters ('url', 'host', 'zone') appear irrelevant to the JSON-validation task, and it does not state the return format. An agent would need to guess what a successful or failed validation looks like.

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 schema already documents all four parameters. The description adds no further meaning about how the parameters relate to the validation operation, leaving the agent to infer that only 'json' matters. Baseline 3 is appropriate since the schema does most of the 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 uses a specific verb and resource: 'Check whether a body is valid JSON.' The purpose is immediately clear and the tool name matches. It does not explicitly differentiate from siblings, but the operation is distinct enough that an agent can infer what it does.

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?

There is no guidance on when to use this tool versus alternatives, no mention of preconditions, and no exclusion criteria. The description simply states what it does, not in what context an agent should choose it over sibling tools like normalize-url or cite.

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