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

With no annotations, the description carries the burden of behavioral disclosure. It does contribute one meaningful behavior: 'Page content is not stored.' However, it does not disclose side effects, network behavior, caching, or what happens with the other schema parameters.

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?

Both sentences are purposeful and the main return value is front-loaded. There is no filler or redundancy, and the text is appropriately short for the amount of intended information.

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 no output schema, no annotations, and several optional parameters, yet the description only covers the URL result. It omits the output format, parameter selection, and any relationship to sibling tools, so an agent may not know how to invoke it correctly.

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 and the description does not need to restate parameter meanings. The description does not clarify which parameter to use for the URL result, and it ignores the several auxiliary parameters in the schema.

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 uses a specific verb and object: it returns host, scheme, and HTTP status for a URL. It is clear on the action, though it does not distinguish this tool from sibling tools such as fetch-status or normalize-url.

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 given about when to use this tool rather than sibling alternatives, and no exclusions or prerequisites are stated. The description only says what it returns, leaving the agent to infer the appropriate call context.

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