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

With no annotations provided, the description must carry the behavioral disclosure burden. It does state 'Page content is not stored,' which is a useful behavioral trait. However, it omits other important aspects such as whether the tool makes network requests, follows redirects, or requires authentication. While the statement about not storing content adds value, the overall behavioral context is thin.

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, well-structured sentence that immediately states the core function and then adds a relevant behavioral note. It is concise, front-loaded, and contains no filler. Every word earns its place, making it an exemplary model of brevity.

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 parameters, the description only addresses the URL aspect and ignores the other parameters entirely. It does not clarify whether those parameters are simply ignored, checked, or part of a broader capability. Additionally, there is no output schema, so the agent does not know the format of the returned host, scheme, and HTTP status. The description is too minimal to fully equip an agent to use this tool correctly among many similar siblings.

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 each parameter has a description in the schema. The tool description adds no additional meaning about parameters—it only refers to 'a URL' without specifying which parameter to use. The schema itself clarifies that 'url' is for the URL, but the tool description does not reinforce this or explain the role of the other 8 parameters. Since coverage is high, the baseline of 3 is appropriate, but the description fails to compensate for the many seemingly irrelevant parameters.

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 clear purpose: 'Return host, scheme, and HTTP status for a URL.' This is a specific verb and resource, making it easy to understand what the tool does. However, it does not distinguish itself from siblings like 'fetch-status' or 'browser-url-ok', which likely have overlapping functionality, so it doesn't fully achieve a 5.

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. The description does not mention any conditions, prerequisites, or explicit comparisons to sibling tools. An agent has no direction on when to prefer 'citation' over similar tools, leaving this decision to inference.

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