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

Annotations already declare the safe-read profile (readOnly, idempotent, non-destructive, openWorld), so the bar is lower. The description adds real operational context beyond them: the 1–10 URL cap, the fact that it fetches any site including competitors, variant/redirect-loop detection, and the Googlebot user-agent fetch that can reveal cloaking.

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 the core purpose, and the long enumeration of audited attributes is dense but each element is a distinct, useful check. It runs as one heavy run-on paragraph, so a modest structural cost, but there is little genuine filler.

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 burden of describing returns, and it does so by listing the per-page findings (issues list, redirect chains, headers, headings, links, structured data). Only the exact shape/format of the response is left unstated, which is a minor residual gap.

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 only 25% — only the urls array ("Up to 10.") is documented — yet the description compensates by explaining check_variants and as_googlebot in behavioral detail and stating the 1-to-10 URL bound that governs both url and urls. This substantially fills the gap left by the bare 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?

States a specific verb and resource ("On-page SEO audit of 1 to 10 URLs") and immediately scopes it (any site, competitors too), which cleanly separates it from site-wide siblings like site_audit. The enumeration of what it examines makes the tool's function unmistakable 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?

Usage context is implied rather than stated: the description explains why check_variants (http/https, www/non-www) and as_googlebot (catches cloaking/bot rules) would be used, which reads as when-to-use guidance for those flags. However, it never names an alternative or says when NOT to use this tool versus gsc_inspect_url or site_audit, so routing is left to inference.

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