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

With no annotations, the description carries full behavioral burden. It discloses 'Body discarded', which is a useful behavioral detail, but it does not explain that the tool appears to handle multiple input types (city, zone, json) or what happens with those inputs. No mention of network behavior, error handling, or return format beyond HTTP status.

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 concise (one sentence) and front-loaded with the core action. However, it is under-specified relative to the tool's apparent multi-parameter nature, so brevity here comes at the cost of clarity. It is not verbose, but it trades completeness for 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 9 parameters, none required, and no output schema, the description is vastly incomplete. It only addresses URL-related behavior while ignoring the other 8 parameters. An agent cannot determine what the tool does with 'city', 'zone', 'json', etc., or when to invoke it. This is a severe gap for a complex 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 already has a description. The tool description adds no extra meaning for any parameter; it only mentions 'URL' generically, while the schema covers all nine parameters. Baseline 3 is appropriate since schema handles parameter semantics adequately.

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 verb and resource: fetching HTTP status for a public library docs URL. However, the parameter list includes unrelated fields (city, zone, json, query), suggesting the tool is actually a multi-purpose checker, so the stated purpose is incomplete and potentially misleading. It is not a tautology, but it fails to convey the full scope of the tool.

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 its many siblings (e.g., fetch-status, browser-url-ok, normalize-url). The description gives no context for selecting this tool over alternatives, and no exclusions or conditions are provided.

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