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

With no annotations, the description carries the full burden. It discloses that page content is not stored, but does not mention other behaviors such as making a network request, handling redirects, or error behavior. The description is partially transparent but leaves important side effects unstated.

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 sentences with no redundant wording. It efficiently conveys the tool's purpose and a key behavioral note, making it easy to parse and understand.

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 description is sufficient for a simple tool, stating what it returns and a storage constraint. It lacks context on when to prefer this tool over siblings or how errors are handled, but given the simplicity, it is mostly complete.

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 provides descriptions for all four parameters (url, host, json, zone), covering their semantics. The tool description adds no extra meaning for these parameters, so the score is at the baseline of 3 for complete schema coverage.

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 clearly states that the tool returns host, scheme, and HTTP status for a URL, which is specific and distinguishes it from sibling tools like normalize-url or status-catalog. The action verb 'Return' and the explicit outputs make the purpose unambiguous.

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 implies when to use the tool—when URL components and HTTP status are needed—but does not explicitly name alternative tools or contrast them. The inclusion of 'Page content is not stored' provides a usage hint about data retention, but a direct reference to siblings would make guidance clearer.

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