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

With no annotations attached, the description carries the full burden for behavioral disclosure. It only says 'The body is discarded,' which implies no persistence, but it does not state the return format (e.g., boolean), error behavior for invalid JSON, or whether other parameters (url, feed, path) are ever accessed. The schema's per-parameter 'discarded' notes add some transparency, but the description itself leaves major behavioral unknowns.

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, which is good for concision. However, the word 'body' diverges from the schema's parameter names, forcing the agent to infer which input is meant. It is short but not optimally precise.

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 a seven-property schema, no required list, no output schema, and an ambiguous 'body' reference, this description is incomplete. An agent cannot determine which parameters to provide, whether any are required, or what the valid JSON check returns. The mismatch between the narrow description and the broad schema makes confident invocation difficult.

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 input schema already provides detailed descriptions for all seven properties, including discard behavior, so the schema coverage is high. The description adds no parameter-specific value beyond introducing the word 'body', which is not a schema property name and actually muddies the mapping to the `json` parameter. Baseline 3 is appropriate because the schema carries the load.

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') and resource ('a body of valid JSON'), and the name validate-json reinforces the purpose. However, it never connects 'body' to the `json` parameter in the schema, and the schema exposes six other parameters (ref, url, city, feed, host, path) that are not mentioned, creating ambiguity about what exactly is 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 given for when to use this tool versus sibling tools like `domain-shape`, `file-path-ok`, or `fetch-status`. There are no exclusions, alternatives, or context conditions stated. The 'discarded' note hints at read-only behavior but does not help an agent decide between validation tools.

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