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

With no annotations, the description carries the full burden for behavioral disclosure. It does add a meaningful side-effect note: 'The body is discarded,' which indicates the input is not persisted. However, it doesn't disclose what the tool returns (boolean, error, message), whether other parameters affect behavior, or any auth/rate-limit constraints. For a safe, read-only validation operation, the discard note is helpful but incomplete.

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 zero filler: the purpose is front-loaded and the side-effect note is a single crisp clause. Each sentence earns its place, even though the tool has a large schema. It is an example of appropriately concise writing.

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?

The tool has nine optional parameters and no output schema, yet the description only names a 'body' without pointing to which parameter supplies that body or explaining the result of validation. An agent must infer from the individual parameter descriptions that 'json' is the input. This is a significant gap for a tool with such a broad schema.

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% — all nine parameters have descriptions in the input schema, so the baseline is 3. The tool description itself adds no parameter meaning beyond implying the 'body' is one of the inputs; it doesn't clarify that only the 'json' parameter matters for this tool. The schema already provides the per-parameter details, and the description does not compensate beyond that.

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 verb and resource — 'Check whether a body is valid JSON' — and is not a tautology. It doesn't explicitly differentiate from sibling shape-checkers like 'file-path-ok' or 'domain-shape', but the tool name and sentence make the core purpose clear. The broad schema with many unrelated optional parameters adds some ambiguity, but the purpose itself is identifiable.

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 about when to use this tool versus the many sibling validators (e.g., 'file-path-ok', 'github-repo-shape', 'wiki-title-ok'). There are no exclusions or references to alternatives, leaving an agent to infer from the tool name alone that 'validate-json' is for JSON checks.

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