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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds real value beyond them by warning that untrusted_* fields carry text controlled by other sites and must be treated as data to show the user, not instructions, and by noting the report references at most 5 of referring_count, percent-encoded. No quota or rate-limit behaviour is disclosed, which keeps it just under 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?

The core statement is front-loaded and the prompt-injection caveat is stated compactly. The trailing 'Tools revision: d80f65c0.' line and the irregular whitespace add nothing an agent can act on, so it is not fully waste-free.

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 no explanation, and the injection warning covers the riskiest aspect of the response. The remaining gap is parameter disambiguation for siteUrl vs inspectionUrl, which an agent cannot infer from a 0%-coverage schema.

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 0% and both required parameters (siteUrl, inspectionUrl) are bare strings with no titles beyond their names. The description only implies the relationship ('a URL under a verified site') and never explains that siteUrl is the verified property identifier and inspectionUrl the exact page to inspect – the single most common point of confusion for this API.

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 description names a specific resource and scope: index status / coverage for a URL under a verified site. That clearly separates it from gsc_search_analytics (performance data) and gsc_request_indexing (a mutation that asks Google to crawl), though it does not call those siblings out by name.

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 line 'Google answers only for pages of the user's own verified site' functions as an implicit when-not constraint and is genuinely useful for avoiding failed calls. However, there is no guidance on when to prefer this over gsc_request_indexing or site_index_audit, and no prerequisites about verifying the property first.

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