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

With no annotations, the description carries the full burden of behavioral disclosure. It discloses that page content is not stored, which is useful, but omits network behavior, error handling, rate limits, or side effects (e.g., whether the URL is fetched server-side). For a tool that validates URLs, this is thin.

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 short and front-loaded with the core behavior and a key limitation. It earns its place with no filler, though it ends abruptly and does not enumerate parameter roles.

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 schema defines four parameters but the description explains only one behavior (returning host/scheme/status). With no output schema and no annotations, the agent lacks context for what happens with json or zone, what the output format is, or when this tool is preferable to the many sibling tools. This is under-specified for a tool with four optional parameters.

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 the schema already describes each parameter individually (url, host, json, zone). The description adds no parameter-specific detail beyond 'host and scheme' for the URL. The presence of open parameters with no required fields and no functional description beyond the schema leaves the agent to rely on schema alone, so baseline 3 is appropriate.

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 verb–resource pair ('Return host, scheme, and HTTP status for a URL') and adds one distinguishing fact ('Page content is not stored'). However, it does not mention other input fields (json, zone) or sibling tools, so the tool's broader purpose is only partially conveyed.

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 gives no explicit guidance on when to use this tool versus alternatives, and the sibling list includes many similarly named tools (normalize-url, validate-json, etc.) with no routing hints. The only contextual clue is the negative statement about page content not being stored, which weakly implies a lightweight citation-checking use case.

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