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

With no annotations provided, the description carries the full burden. It discloses that the body is discarded, which is useful, but it doesn't explain what 'body' refers to (likely the 'json' parameter), whether the tool returns a result (e.g., true/false), or how the other schema parameters (url, host, zone) relate to validation. This lack of detail is a significant gap 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 two short sentences with no wasted words. It front-loads the primary purpose and adds a key behavioral note about discarding the body. This is concise and well-structured.

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 simple validation tool, the description is incomplete. It doesn't specify which parameter holds the JSON to validate, what the return value is (there is no output schema), or how the other parameters are used. The schema lists unrelated parameters (url, host, zone) that are not explained, leaving an agent unsure how to invoke the tool correctly.

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 descriptions for all four parameters, so the baseline is 3. The tool description adds no parameter-specific meaning; it only mentions 'body' without mapping it to the 'json' parameter. Since it doesn't contradict the schema and the schema itself is descriptive, the baseline holds, though the description misses an opportunity to clarify which parameter is the body.

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 clearly states the action (check) and the resource (whether a body is valid JSON), which distinguishes it from sibling tools that handle URLs, timezones, or HTTP statuses. However, it doesn't explicitly differentiate itself from any sibling that might also handle JSON, and the presence of unrelated parameters in the schema slightly clouds the purpose.

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 prerequisites, and no exclusions. The description simply states what it does without any context for selection, leaving an agent to guess when it is the appropriate choice among the sibling tools.

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