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

Annotations already declare the safe read-only, idempotent, non-destructive profile. The description adds genuinely new context beyond them: the GSC connection prerequisite, where to connect it, and how ambiguity resolves when multiple Google accounts are linked (read via the account that can see the property).

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 what it returns, then use cases, then prerequisites. Four sentences, each carrying distinct information; slightly padded but no wasted lines.

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?

For a read-only GSC tool, it covers purpose, use cases, auth prerequisite, and multi-account behavior. No output schema exists, but the description names the metrics returned, which is enough; missing only pagination/volume limits.

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% and all three parameters (site, startDate, endDate) are documented in the schema with format hints. The description adds no extra parameter detail such as date-range limits, so baseline 3 is appropriate.

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 (Get) plus resource and scope: daily search performance trends across four named metrics (clicks, impressions, CTR, position) over a date range. An agent can distinguish it from the page/query-level trend siblings by the site-wide daily grain. It never names an alternative sibling, so it stops short of a 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?

Gives concrete situations of use (spotting ranking changes, traffic drops, algorithm update impact) and a hard prerequisite that Google Search Console must be connected, with the exact setup URL. No when-not or explicit alternative sibling is named, so it is clear context without exclusions.

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