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

Beyond the readOnly/non-destructive annotations, the description discloses critical interpretation rules that are easy to get wrong: value fields are null on a query variant or a page canonicalised elsewhere, with valueCountedOn naming the URL that actually carries the metrics, and 'null = not read for this page, never fine.' That prevents an agent from reading absence as a zero or a clean result, which is exactly the kind of behavior annotations cannot convey.

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 subject is front-loaded well in the first clause, but the remainder is a single sprawling sentence built from nested parenthetical lists, which is hard to parse at speed. Almost no words are redundant, yet the structure sacrifices scannability for density.

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 must carry the return-value burden and largely does: it names the crawl facts, value metrics, issue findings, per-crawler robots.txt decisions with their governing rule, URL Inspection verdict, and Core Web Vitals window. Minor gaps remain — it does not explain how a crawl is chosen when crawlId is omitted (left to the schema) or what happens for an unknown URL.

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%, so all three parameters (url, crawlId defaulting to the latest completed crawl, clientId) are already documented, and the description adds no syntax, format, or constraint details for them. Baseline 3 applies when the schema carries the parameter burden.

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 opening clause 'One URL of a client's SEO audit crawl' gives a specific resource and scope, and the parenthetical enumeration (status, redirect, timing, indexability, title, H1, canonical, depth, links in) makes clear this is the per-URL detail view, not the crawl-level summary (get_site_audit) or the issue list (list_site_audit_issues). An agent can tell it apart from its siblings without opening the 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?

There is no explicit when-to-use statement, no exclusions, and no named alternative in the description itself; the only routing hint ('list_site_audit_pages') lives in the input schema. Usage is implied by the shape of the resource — fetch this after finding a URL in the page list — but the agent must infer it.

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