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

With no annotations, the description carries the behavioral disclosure burden. It discloses the HTTP method (HEAD), the public scope, and the restricted output. However, it does not mention redirect handling, error behavior, or that many schema parameters are 'discarded after the shape check,' which is important behavioral context given the input schema.

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. Every word contributes to the core action and output. It is concise without being vague.

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 annotations, and no output schema, yet the description only addresses HEADing a URL. It does not explain how to invoke the tool with ref, city, feed, json, path, query, timezone, or zone, nor what 'status only' concretely returns. This is a significant completeness gap for a 9-parameter 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 description coverage is 100%, so the parameters are already documented in the schema. The description adds no parameter-level meaning beyond identifying 'URL' as the primary input, which matches the schema. Baseline 3 is appropriate because the schema does the heavy lifting.

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 action and output: 'HEAD a public URL and return status only.' This clearly distinguishes it from body-fetching tools like web-fetch, though it does not explicitly name sibling alternatives. It is a clear purpose statement, but it only describes the URL mode and does not account for the many non-URL parameters in the schema.

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 phrase 'return status only' implies this is for lightweight status checks rather than content retrieval, but there is no explicit when-to-use or when-not-to-use guidance. Alternatives like browser-url-ok or playwright-url-ok are not mentioned, leaving the agent to infer when this HEAD-based tool is preferred.

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