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

The annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile is covered. The description adds that two separate surfaces (AI Overview and AI Mode) are queried, but it says nothing about freshness or caching, latency/cost of an external SERP call, or whether the two surfaces are reported separately or merged.

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?

A single front-loaded sentence naming the action, the target surfaces, and the two inputs, with no filler. Nothing could be cut without losing meaning.

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?

There is no output schema and no parameter documentation, so the description carries most of the burden. It does convey the essence of the answer (presence versus citation) and names both surveyed surfaces, but it leaves the return shape, the meaning of the country default, and result freshness unspecified.

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%, so the description must compensate, and it only implicitly covers 'domain' and 'keyword'. The 'country' parameter, including the default 'us' and how it affects geo-specific AI Overview results, is not mentioned anywhere and is therefore undocumented in both places.

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 gives a specific verb ('Check') and a precise resource ('Google AI Overview and AI Mode'), and states that it answers whether a domain 'appears in / is cited by' the surface for a keyword. This distinguishes it from the sibling rank_check, which suggests a classic ranking lookup, though it does not directly name that sibling.

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, when-not-to-use, or alternative-tool guidance. The agent must infer from the verb 'Check' that this is a point-in-time lookup, and nothing says when rank_check or page_meta would be the better choice.

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