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

With no annotations, the description must carry the behavioral disclosure burden. It does reveal a key side effect: 'The body is discarded.' However, it does not disclose what happens for invalid JSON, what the return value is, or whether any of the url/feed/host/path parameters cause network or file access.

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 extremely concise at two short sentences. The primary purpose is front-loaded, and the discard side effect is stated without wasted words.

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?

Despite nine parameters and no output schema or annotations, the description only covers a minimal validity check and a discard side effect. It does not explain the role of unrelated-looking parameters (url, city, feed, host, path, zone, query), the output format, or error behavior, leaving the tool under-specified for reliable invocation.

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 nine parameters in detail. The description adds no parameter-level meaning beyond referring vaguely to a 'body,' which does not clearly map to the 'json' parameter.

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 action and resource: 'Check whether a body is valid JSON.' This clearly distinguishes it from validation siblings like browser-url-ok or wiki-title-ok, though it does not explicitly name or contrast those alternatives.

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 prefer this tool over other shape/validity checkers such as file-path-ok or domain-shape. The description only implies a validation use case but provides no context, prerequisites, or exclusions.

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