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

There are no annotations, so the description carries the full burden. It does disclose that the body is discarded and narrows the result to status and content type. It does not mention redirects, timeouts, HTTP method, or behavior for unavailable URLs, which are relevant for a network-fetch tool.

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, both informative and front-loaded. 'HTTP status and content type for a public URL' states the core result first, and 'Body discarded' adds an important limitation without extra wording.

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 a nine-parameter schema, no annotations, and a large sibling set, this description is too sparse. It does not explain which parameter to use, what the output format is, how failures are returned, or how this tool relates to fetch-status and similar tools.

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%, with each of the nine parameters described, so the baseline is 3. The description adds little parameter-specific meaning beyond indicating the tool is about public URLs, and it does not clarify which of the many parameters is the primary one for the fetch operation.

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 what the tool does: it returns HTTP status and content type for a public URL, and explicitly says the body is discarded. This distinguishes it from full-content fetchers, though it does not name or differentiate from closely related siblings like fetch-status or browser-url-ok.

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 'public URL' qualifier and 'body discarded' provide an implicit sense of when to use this tool: for lightweight status/content-type checks rather than retrieving content. However, it gives no explicit guidance on when not to use it or which sibling tool should be chosen instead.

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