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

Annotations already declare readOnlyHint=true, openWorldHint=true, destructiveHint=false, so the safety profile is covered; the description usefully adds result shape ('one row per date, sorted oldest-to-newest') and a retention claim. Beyond that it says nothing about rate limits, quota cost of long ranges, or empty-result behavior for queries with no history. Decent additive value, but thin for a tool whose main selling point is deep historical pulls.

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?

Front-loaded with the return payload, then scope, then shape, then an example — three short blocks with no filler. The line breaks read a bit like stream-of-consciousness, but every sentence carries information.

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?

With an output schema present, the description rightly doesn't need to enumerate return fields, and it covers scope and ordering. The remaining hole is date-parameter format/interpretation, which is missing from both schema and description for a tool that depends entirely on arbitrary ranges.

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 coverage is 50%: 'query' and 'site_url' are documented in the schema (including the % partial-match trick), but start_date and end_date have no description anywhere and the description does not supply a date format or timezone. The description reinforces that the query is singular and the range is unbounded, which adds modest meaning, but the two date params remain undocumented.

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 and payload: daily clicks/impressions/CTR/position for a single query, plus the differentiator 'Goes back to whenever your archive started (no 16-month limit)'. That scope statement separates it from the standard-GSC-window siblings, though it never names the sibling that carries the 16-month limit (e.g. search_analytics_query).

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?

Gives clear triggering context ('over any date range', 'no 16-month limit') and a concrete example use case ('show me how workshop has been doing all year'), which tells an agent when this tool is the right pick over a shorter-window query. It stops short of naming alternatives or stating when not to use it.

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