Quick wins

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

Annotations already declare readOnly/idempotent/non-destructive, so safety is covered. The description adds real behavioral value on top: it discloses the default thresholds and clarifies the ctr fraction semantics. The note that it does not estimate missed clicks usefully bounds the result semantics, though it doesn't discuss ordering or how many rows appear absent an explicit limit.

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 short sentences, zero filler, and the defining filter is front-loaded ahead of the tuning defaults. Every sentence earns its place, including the scope-limiting final clause.

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 description correctly focuses on the filters that define the query. The main remaining gap is the default date window and defaults for device/country/searchType, which an agent would need to know before calling.

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% across 9 parameters, so the description must compensate. It does so well for the two trickiest thresholds (minImpressions default 100, maxCtr default 0.02 and its fraction interpretation) but says nothing about limit, device, country, date range, searchType, or siteUrl. Partial compensation, so a 3 rather than higher.

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 resource (Search Console queries) and the precise filter that defines the set: high impressions, low ctr. An agent understands the shape of the output without opening the schema. It doesn't explicitly name a sibling (e.g. top_queries) to contrast against, so it stops short of 5.

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 description supplies the operative defaults (>=100 impressions, ctr <=0.02), which tells the agent how to invoke it, but gives no when-to-use vs alternatives such as top_queries or top_pages, and no exclusion guidance. Usage context is implied by the topic rather than stated.

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