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

Annotations already declare readOnly/idempotent/openWorld, and the description adds value beyond them: per-URL live-call latency, the owner-level Search Console access requirement, and the explicit failure mode ('comes back unavailable with an explanation'). That is exactly the behavioral context an agent needs before invoking.

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?

Three sentences, zero waste, and front-loaded: the capability comes first, then the cost trade-off, then the access prerequisite. Every clause earns its place.

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?

An output schema exists, so return values need not be explained. Latency, auth requirement, failure behavior, and the sibling alternative are all covered, leaving nothing an agent needs 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?

Only one parameter at 100% schema coverage, so the schema already documents the url field fully ('Full storefront URL on this store'). The description reinforces the single-page scope but adds no syntax or format detail beyond the schema. Baseline 3 is appropriate.

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+resource+scope: 'Definitive index check for ONE page' from Google's URL Inspection API, enumerating the concrete outputs (indexed or not, coverage state, verdict, last crawl, canonical). It is immediately distinguishable from the sibling get_indexing_status, which it names.

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?

Explicitly routes between alternatives: 'Slower than get_indexing_status because it makes a live call per URL, so use it to confirm a specific page rather than to sweep the store.' Both the when-to-use and when-not-to-use conditions are stated, plus the access prerequisite.

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