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

With no annotations, the description carries the full burden of behavioral disclosure. It states that it performs a HEAD request and returns only status, which hints at non-destructive behavior. However, it does not disclose any side effects, authentication needs, rate limits, or what happens with non-URL parameters. The disclosure is minimal and leaves much to inference.

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 extremely concise, a single sentence, and front-loaded with the core action. However, it is under-specified for a tool with 9 optional parameters and no output schema. It is not verbose but lacks structure and depth, so a 3 is fair.

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 optional parameters, no output schema, and no annotations, yet the description is only one vague sentence about HEADing a URL. It does not explain how the other parameters are used (though the schema does mention they are discarded), what 'status' means, or how the tool behaves with different inputs. It is severely incomplete for the tool's complexity.

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 schema fully documents all 9 parameters, including that many are discarded. The description adds no parameter-level meaning beyond the schema. It mentions 'public URL' but does not map this to the 'url' parameter explicitly. Baseline 3 is appropriate since the schema handles parameter documentation.

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: 'HEAD a public URL and return status only.' It is clear and distinguishes from siblings like normalize-url or web-fetch, but it does not explicitly differentiate from browser-url-ok or playwright-url-ok, which also check URLs. A 4 is appropriate because it is clear but lacks explicit sibling differentiation.

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 provides no guidance on when to use this tool versus alternatives. It does not mention any conditions, exclusions, or reference to sibling tools. There is no context about use cases, prerequisites, or when to prefer it over other URL-checking tools.

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