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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so safety is covered. The description adds genuine behavioral context beyond them: rows are only dates the API returned, missing dates are not backfilled, and ctr is an unfractioned API value rather than a percentage. It omits row limits/pagination, which is the remaining gap.

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, each carrying distinct information (what the rows are, gap semantics, unit semantics), with the core output description front-loaded. No filler or restatement of the title.

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-value explanation is not needed, and the gap/unit notes are useful. However, with 6 parameters at 0% schema coverage the description leaves the agent guessing about the date range and filter parameters, which is a material omission for a trends tool.

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 6 parameters, so the description carries the full burden, yet it documents none of them. Only 'for a property' loosely gestures at siteUrl and 'daily' implies a date range; startDate, endDate, device, country and searchType are never mentioned, and the description does not clarify whether the date range is required.

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 the resource (daily Search Console metrics for a property) and the granularity (one row per date), which is a clear verb-less but specific purpose. It does not distinguish itself from close siblings like compare_periods or top_queries, leaving the agent to infer the boundary.

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 guidance and no named alternative, even though compare_periods and top_queries are plausible overlaps. Usage must be inferred entirely from the phrase 'Daily ... for a property'.

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