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

With no annotations provided, the description must disclose behavior. It states that query and fragment are dropped, which is useful, but it entirely omits the behavior of the other eight parameters (e.g., ref, city, feed), whose schema descriptions mention 'discarded after the shape check' – a behavior not explained in the main description. This leaves significant ambiguity about what the tool actually does with non-URL inputs.

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, front-loaded sentence with no filler. It is concise and direct. However, given the complexity of the schema (9 parameters), the brevity sacrifices necessary detail, so it earns a 4 rather than a 5.

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 9 parameters, none required, and no output schema. The description explains only the URL handling and says nothing about the other parameters, the shape-checking behavior implied by the schema, the return format beyond the three components, or error conditions. This is grossly inadequate for an agent to correctly invoke the tool.

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 coverage is 100%, so each parameter has a description, but those descriptions are confusing and misaligned with the tool's stated purpose. For example, 'ref' is described as 'Git ref name; discarded after the shape check', which implies a shape-checking behavior not mentioned in the main description. The parameter descriptions do not clarify how the url parameter relates to the others or how to use them correctly.

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 core function: return origin, host, and path for a URL, with query and fragment dropped. This is a specific verb+resource statement. However, it does not differentiate from siblings like 'domain-shape' or 'browser-url-ok', and the schema includes many unrelated parameters, so the overall purpose is only partially clarified.

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?

The description gives no guidance on when to use this tool versus alternatives such as 'domain-shape' or 'fetch-status'. It does not mention any context or exclusions, leaving the agent to infer appropriate usage.

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