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

With no annotations provided, the description carries the full burden of behavioral disclosure. It does add a meaningful statelessness guarantee: 'Page content is not stored.' However, it does not clarify whether redirects are followed, how HTTP status is obtained, whether rate limits apply, or what happens with invalid URLs. The single disclosure is useful but not comprehensive.

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 no filler. The core behavior is front-loaded, and the second sentence adds a meaningful caveat. Every word earns its place.

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 4 optional parameters with no output schema, and the description only covers the URL use case. An agent seeing 'host', 'json', and 'zone' would not know whether to pass them, whether they are inputs or outputs, or what the return shape looks like. The description is insufficiently complete for confident 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% and each parameter has a reasonable description, so the baseline is 3. The tool description adds minimal value beyond the schema, only implying that 'url' is the central parameter. Notably, it does not explain how the 'host', 'json', and 'zone' parameters relate to the stated URL-focused behavior, leaving an ambiguity that the description should have resolved.

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: 'Return host, scheme, and HTTP status for a URL.' This clearly explains the tool's primary function. It does not explicitly distinguish itself from siblings like normalize-url or inspect-robots, but the stated output scope is specific enough to infer a unique purpose.

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?

The description provides no guidance on when to use this tool versus alternatives such as validate-json or normalize-url, which appear in the sibling list. It also does not mention prerequisites, required inputs, or situations where this tool is appropriate or not. The context is purely implicit in the action described.

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