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

Annotations already declare this as read-only, idempotent, and non-destructive, so the description does not need to re-cover safety. It adds useful behavioral detail: a network fetch happens, only a single URL is processed, and the response reports specified robots signals rather than link extraction.

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 one focused sentence with the primary action and scope stated first, followed by a precise negative qualifier. There is no redundant or filler language.

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?

With only one required parameter, full schema coverage, and safety annotations, the description provides enough for an agent to call the tool and understand the returned signals. It does not specify the exact response format or error behavior, but that is not critical for this simple read-only operation.

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 fully documents the only parameter (`url` as 'Page URL, including https://'), so the baseline is 3. The description reinforces that the tool fetches a single URL but adds no meaning beyond the schema.

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 uses specific verbs ('Fetch' and 'report'), identifies the resource ('one URL'), and names the exact outputs (HTTP status, meta robots / X-Robots-Tag noindex and nofollow signals). The phrase 'without extracting links' further distinguishes it from the link-focused sibling tools.

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 intended use is implied: checking robots signals on a single page. The phrase 'without extracting links' suggests this is not for link auditing, but it never explicitly names alternatives or states when to prefer link_audit/link_check over this tool.

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