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

With no annotations, the description carries the behavioral burden. It does add a meaningful privacy guarantee—'Page content is not stored'—and discloses the core output. However, it does not discuss network behavior, redirects, failures, or whether the operation performs a live fetch, leaving important behavioral gaps.

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 filler. The primary output is stated first, and the privacy note earns its place by conveying an important behavioral boundary.

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?

Despite the simple phrasing, the tool accepts several parameters and has no output schema or annotations. The description does not specify the primary parameter, return shape, error behavior, or how the unrelated-looking parameters like city, feed, and json relate to the tool's purpose. This is insufficient context for reliable 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?

The input schema is fully described (100% coverage), so the description need not repeat parameter details. The description adds little parameter-level meaning beyond 'for a URL,' making the baseline 3 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 specific verb and outcome: 'Return host, scheme, and HTTP status for a URL.' It makes the core purpose clear, but it does not explicitly distinguish this tool from closely related siblings such as fetch-status or normalize-url, so it falls short of full differentiation.

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?

There is no guidance on when to use this tool versus alternatives like web-fetch, fetch-status, or browser-url-ok. The privacy note 'Page content is not stored' hints at a use case, but no explicit when/when-not or alternative routing is provided.

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