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

With no annotations, the description carries the full burden, and it does disclose one meaningful behavioral trait: 'The body is discarded.' This tells the agent the input is consumed and not retained. However, it omits critical behavior for a validation tool—what happens on invalid JSON (returns a boolean? throws? produces an error report?)—and discloses no other side effects.

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?

Two short sentences deliver the core purpose and a key behavioral caveat with zero filler. The primary action is front-loaded, and the discard warning earns its place because it changes how an agent should think about the call.

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 four parameters, no output schema, and no annotations, the description is too sparse to be complete. It doesn't explain the irrelevant-looking url/host/zone parameters, doesn't specify the return value or error handling for invalid JSON, and offers no guidance on how this tool relates to the siblings. An agent would likely be confused about which parameters to populate.

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 baseline is 3. The description reinforces that the 'json' parameter's content is discarded, matching the schema's 'discarded after the check.' Yet the schema's other parameters (url, host, zone) have descriptions clearly copied from sibling tools ('HTTPS URL to normalize or cite', 'IANA timezone name'), and the tool description does nothing to clarify why they exist on validate-json.

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, specific action: 'Check whether a body is valid JSON.' The verb 'check' plus the resource 'JSON body' makes the tool's function obvious. It does not explicitly differentiate from the sibling tools (normalize, cite, status, timezone), but the purpose is self-evidently distinct from them.

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?

Usage is implied: an agent would call this when it needs to verify whether some text is valid JSON. However, there is no explicit guidance about when to use this tool versus the siblings, no exclusions, and no mention of prerequisites or whether the tool is appropriate for large bodies.

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