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

With no annotations, the description carries the burden of disclosing behavior. It meaningfully states 'Page content is not stored' and lists the exact returned values. However, it does not mention side effects, error behavior, network behavior, or that several accepted parameters are discarded.

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?

Two concise sentences with no filler. The purpose is front-loaded, and the second sentence adds a meaningful behavioral guarantee about non-storage.

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 core return values are stated, which is useful since there is no output schema. However, with nine optional parameters, no annotations, and several apparently unrelated fields, the description is too terse to fully orient an agent. The schema partially compensates by describing each parameter, but the tool-level picture remains ambiguous.

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%, so the baseline is 3. The tool description adds no parameter-level information and does not clarify which of the many optional parameters are actually relevant to the URL citation behavior. The schema itself provides the discard notes, but the description does not tie them together.

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 the action and resource: 'Return host, scheme, and HTTP status for a URL.' This is a specific verb and output, and the focus on URLs distinguishes it from non-URL siblings. It doesn't explicitly distinguish itself from fetch-status or web-fetch, so it loses a point.

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 about when to use this tool versus the many URL-related siblings such as normalize-url, fetch-status, or web-fetch. 'Page content is not stored' hints at a citation use case, but no explicit when-to-use or when-not-to-use guidance is provided.

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