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

With no annotations, the description must disclose behavioral traits. It states the body is discarded, which clarifies no persistence, but it does not explain the return value (e.g., boolean, error) or side effects. The presence of unrelated parameters (url, host, zone) further obscures behavior—whether they are inputs or ignored. This is insufficient for an agent to know how the tool behaves.

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 with no filler, directly stating the purpose and the disposal behavior. It is efficiently front-loaded and easy to parse.

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 4 parameters and no output schema or annotations, the description is severely incomplete. It does not specify the return type, how to interpret results, or what to do with the extra parameters. An agent cannot reliably invoke this tool correctly without additional information.

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 covers all parameters with descriptions, giving a baseline of 3. However, the tool description adds no value beyond the schema and even introduces ambiguity by referring to 'body' without mapping it to the 'json' parameter. The roles of 'url', 'host', and 'zone' remain unexplained in the description, leaving the agent unsure why they exist for a JSON validation tool.

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 action ('Check whether a body is valid JSON') and identifies the resource (JSON body). It distinguishes from siblings since no other tool appears to do JSON validation. However, the use of 'body' is ambiguous given the schema includes 'url', 'host', and 'zone' which are not clearly related to JSON validation, creating potential confusion about which input is being validated.

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 provided on when to use this tool versus alternatives. It does not mention any exclusions, prerequisites, or alternative tools. For a tool with unrelated sibling tools, the description should at least clarify that it is the go-to for JSON validation, but it does not.

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