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

With no annotations, the description carries the full behavioral burden. It does disclose one useful trait ('Page content is not stored'), but it does not mention whether the tool performs network fetches, whether it requires any auth, what side effects occur, or how the URL is processed. For a tool with no annotation safety signals, this is insufficient.

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 short sentences with no filler. The primary behavior is front-loaded, and the privacy note earns its place as a meaningful behavioral caveat.

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 tool has nine parameters, no output schema, and many closely related siblings, so the burden on the description is high. It covers only the primary URL behavior and ignores the additional schema fields, selection criteria, and edge cases. An agent would likely struggle to know how to call this tool correctly in unfamiliar contexts.

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 even though the description adds no parameter-level detail. The tool description only mentions 'a URL,' while the schema has nine parameters, several of which appear unrelated and are described as discarded. The description does not help disambiguate which parameter is primary or how the others relate to the tool's purpose.

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 and resource: 'Return host, scheme, and HTTP status for a URL.' This clearly identifies the core output, making it more informative than a generic tool name. However, it does not explicitly differentiate itself from siblings like fetch-status, normalize-url, or web-fetch, though its output tuple is distinct.

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?

No guidance is provided about when to use this tool versus alternatives such as fetch-status, normalize-url, or web-fetch. The description implies it is for URL metadata, but it never states what scenarios favor this tool or what it is not suited for.

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