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

No annotations are present, so the description carries the behavioral burden. It does disclose the key behavior that the body is discarded and restricts usage to public URLs, but it omits details such as redirect handling, authentication expectations, response representation, and what happens to the other schema fields.

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?

Two short sentences deliver the core purpose and the most important behavioral caveat with no filler. The key information is front-loaded and every word contributes.

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?

This is a sparse description for a tool with no output schema, no annotations, and a multi-field input schema. It adequately states the core behavior, but leaves gaps around return format, redirect behavior, and why several parameters are present yet described as discarded.

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 input schema provides descriptions for all eight parameters, so the schema already carries most parameter meaning. The description only adds the 'public URL' constraint and does not clarify which parameter is the primary input or reconcile the schema's 'normalize or cite' wording with the described fetch behavior.

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 tool reports HTTP status and content type for a URL, and it adds the useful detail that the body is discarded. This distinguishes it from content-fetching tools, though it does not explicitly differentiate it from the sibling fetch-status 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?

The phrase 'public URL' gives a scope, and 'body discarded' implies the tool is for lightweight header/status checks rather than content retrieval. However, it does not name alternatives or state explicit when-not-to-use conditions, despite several related sibling tools being available.

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