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

Annotations already declare readOnly/idempotent/openWorld/non-destructive, so the bar is lower; the description adds genuinely useful context beyond them: GSC must be connected, where to send the user to connect it, and how the property is resolved when multiple Google accounts exist. It does not cover rate limits or how much history is available, 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?

Front-loaded with the core purpose, then prerequisites, then the multi-account edge case in order of likely need. Four sentences, all substantive; the multi-account sentence is slightly tangential but prevents a real failure mode.

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?

No output schema exists, so the description usefully names the returned metrics (clicks, impressions, CTR, position) at daily granularity, and it covers the auth/connection prerequisite. What's missing is any indication of date-range limits or data freshness, which matters for a time-series 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 100%, including the searchType enum and its caveat about discover/googleNews not supporting query — the description repeats none of this and adds no parameter-level detail. Baseline 3 applies since the schema carries all parameter meaning.

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 verb and resource with scope: 'daily click/impression/CTR/position trend for a specific search query.' The 'specific search query' framing implicitly separates it from get_gsc_date_trends (site-wide) and get_gsc_page_trend (page-level), but no sibling is named explicitly, so an agent must infer the boundary from names alone.

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?

'Use this to track how a particular keyword's ranking and traffic evolves over time' gives a clear use context, and the connection prerequisite plus the dashboard link tells the agent what must be true before calling. It stops short of stating when to prefer get_gsc_query_pages or get_gsc_query_page_pairs instead.

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