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 states 'Page content is not stored,' which is a useful privacy note, but it does not disclose whether the tool makes network calls, is read-only, or how it handles the many other parameters. The description is too sparse to give a complete behavioral picture.

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 that states the core function and a key behavioral fact. There is no fluff, and it is front-loaded with the purpose.

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 the tool has 9 optional parameters, no required ones, and no output schema, the description is incomplete. It only explains the URL-related behavior and ignores the other parameters entirely, leaving the agent uncertain about how to invoke the tool correctly when multiple inputs are possible. More detail about parameter interactions and expected output format would be needed.

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 has 100% coverage with each parameter described (e.g., 'ref' is 'discarded after the shape check'). The tool description adds minimal meaning beyond the schema; it mentions 'URL' but does not explicitly link it to the 'url' parameter. Since schema coverage is high, a baseline of 3 is appropriate, but the description could have clarified which parameter is primary.

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: 'Return host, scheme, and HTTP status for a URL.' This clearly identifies the primary resource and output, and it is distinct from sibling tools like normalize-url or fetch-status. However, it does not mention the other eight optional parameters, so the full scope is unclear, but the core purpose is 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 provides no guidance on when to use this tool versus alternatives such as fetch-status or normalize-url. It does not mention any conditions, prerequisites, or exclusions, leaving the agent to infer usage from the name and description alone.

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