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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false, and openWorldHint, so safety is covered. The description adds useful behavioral context beyond annotations: it requires GSC to be connected, gives a URL for connection, and explains that when multiple Google accounts are connected the property is read through the account that can see it. It does not cover rate limits or error behavior.

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?

The description is four sentences, front-loads the core purpose, then provides usage context, prerequisites, and multi-account behavior. Every sentence earns its place with no redundancy.

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?

Given four required parameters, full schema coverage, no output schema, and rich annotations, the description covers purpose, usage, connection prerequisite, and multi-account nuance. It does not specify the return shape (e.g., array of daily rows) despite the lack of an output schema, leaving a small gap for an agent that needs to know the response format.

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%, so the schema already documents all four parameters with examples and formats. The description does not add any parameter-level syntax, constraints, or meaning beyond what the schema provides, so the baseline score of 3 applies.

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?

The description gives a specific verb ('Get') and resource ('daily click/impression/CTR/position trend for a specific page'), and the page-specific scope clearly distinguishes it from siblings like get_gsc_date_trends or get_gsc_query_trend. An agent can tell what it does without opening the schema.

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?

It explicitly states when to use it ('to see how a single page's search performance has changed over time, useful for measuring the impact of a content update or spotting a ranking drop'). However, it does not name alternative tools or state when not to use it, so it falls short of the top score.

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