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

With annotations already covering read-only/idempotent/open-world, the description adds real context: 5-15 second latency, capped free-limit shared across audits, non-product pages being free and non-erroring, and email-gated unlock for details. It does not say whether results are cached or whether repeated calls on the same URL are free, which keeps it from a 5.

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?

Front-loaded with what the tool returns before the operational notes; every clause carries information. Slightly dense, listing the full return payload in one long sentence, but nothing is redundant.

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?

No output schema exists, so the description carries the full burden of describing the response (score, grade, platform, category scores, top issues, 19 check statuses, Q&A table, shareable link) and it does so thoroughly, plus latency and gating expectations.

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 baseline is 3. The description adds meaningful parameter semantics for the single `url` field — it must be a product page, and homepage/other pages are handled gracefully rather than failing — which helps the agent pick the right input and set expectations.

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 ("Runs the ROAS Expert product page check on one product URL") with a clear scope boundary against audit_site. An agent can distinguish it from audit_site, get_report, and explain_fix without opening any schema.

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?

Explains the preconditions (pass a product page URL, not a homepage) and names the follow-up path (unlock_report with work email) plus the shared free limit with audit_site. It stops short of explicitly saying "use audit_site if you have a homepage," but the routing signal is strong.

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