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

The only behavioral disclosure is that it avoids WHOIS/ownership lookups, which is useful but minor. With no annotations, the description must carry the full burden, yet it omits what happens to the other eight parameters, whether there are side effects, or what the output format is. The parameter descriptions hint at discarding data, but the tool description does not.

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, which is concise, but it is under-specified for a tool with nine parameters. It front-loads the hostname action but does not earn its place by explaining the tool's actual breadth, making it more terse than useful.

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 parameters, no output schema, and no annotations, yet the description only covers hostname splitting. It fails to explain how the other parameters fit, what the tool returns, or how the tool behaves across inputs. This is severely incomplete for a multi-purpose shape checker.

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 already has 100% coverage with each parameter documented, so the baseline is 3. The description adds no additional parameter semantics beyond the schema's own descriptions, and it does not help map the unrelated parameters to the stated hostname-splitting purpose.

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 ('split a hostname into labels') and a constraint ('without WHOIS or ownership data'), which is clear for that single use case. However, the input schema accepts nine unrelated parameters (url, city, feed, json, path, zone, query, ref), so the description does not reflect the tool's full scope and could mislead an agent into thinking it only handles hostnames.

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 provided on when to use this tool versus its many siblings (e.g., figma-url-shape, github-repo-shape, jira-key-shape) or when not to use it. The description gives no context for selection, leaving the agent to infer the intended use from the schema alone.

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