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

With no annotations, the description carries the burden of behavioral disclosure. It states 'Body discarded', which tells the agent that content is not returned, and implies the tool is read-only and safe for public URLs. However, it omits details on error behavior, rate limits, or any side effects, leaving significant gaps.

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, using a single sentence with two clauses. It is front-loaded with the core purpose and quickly states the body-discarding behavior. While it is not overly verbose, it is so short that it borders on under-specification rather than elegant conciseness.

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, all optional, and no output schema, the description is severely incomplete. It claims to return HTTP status and content type for a URL, but the parameters include ref, city, feed, host, json, path, zone, and query, which are not explained in the description. An agent cannot determine how these parameters influence the tool's behavior or whether they are used at all. The description fails to cover the tool's full scope.

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?

The schema has 100% coverage, with each of the 9 parameters having its own description. The tool description adds no additional meaning beyond what the schema already provides, so the baseline of 3 is appropriate. It does not clarify how the many seemingly unrelated parameters (city, zone, query, etc.) relate to the stated purpose of HTTP status/content type.

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 it fetches HTTP status and content type for a public URL, with body discarded. This is a specific verb and resource, but it doesn't differentiate from siblings like fetch-status or browser-url-ok, which may overlap. Without comparison, the purpose is clear but not unique among the sibling set.

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?

No guidance is provided on when to use this tool versus alternatives like fetch-status, normalize-url, or browser-url-ok. There is no mention of conditions or exclusions, leaving the agent to infer usage from the name and description alone.

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