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

Annotations already declare readOnly, idempotent and open-world, so the safety profile is covered. The description adds genuinely non-structured context: personal-name addresses are deliberately excluded, only one homepage fetch occurs, and broken HTTPS is flagged. That is meaningful disclosure beyond the annotations.

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?

A single dense paragraph that front-loads what is read and what is returned, with the constraint trailing. Every clause carries information, though the parenthetical CMS list and email prefixes make it longer than strictly necessary.

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 no output schema, the description carries the full burden of describing return values, and it does so field by field. Combined with annotations covering the safety profile, an agent has everything needed to call this correctly.

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 coverage is 100% and the single 'domain' parameter is fully documented in the schema (domain or URL, with examples). The description adds nothing about accepted input formats, so the baseline 3 is correct — the schema does all the work.

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?

Specific verb+resource: reads a business website's homepage and enumerates exactly what it returns (title, CMS, emails, phone, socials, contact URL). An agent knows precisely what data comes out. It does not explicitly distinguish itself from the sibling check_https, even though the 'flags a broken HTTPS certificate' clause overlaps that tool's territory.

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 closing clause 'Public websites only; one homepage fetch' gives a scoping constraint, and the return list implies use for business/contact enrichment. But there is no explicit when-to-use vs. the sibling check_https, and the HTTPS overlap is unresolved, so routing still requires inference.

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