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

The readOnlyHint annotation already establishes safety, and the description adds useful behavioral context: weekly is the default, daily is chosen via granularity=day, Plausible data is included where connected, and responses use the account language. It does not describe response shape or edge cases, but the annotation lowers that burden.

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 sentences, front-loaded with the tool's purpose and followed by operational defaults and a useful response-language note. There is no wasted wording.

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 trend tool with a fully documented schema and no output schema, the description covers the core purpose, defaults, and notable data-source context. It could be slightly stronger with explicit sibling routing or response-structure notes, but nothing critical is missing.

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 input schema already defines all four parameters and their defaults. The description reinforces the path scope, granularity choice, and default weekly behavior, but adds only modest meaning beyond the schema.

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 states a specific verb and resource: 'Search performance over time' for the whole site or a single page, framed as trend detection. It is clear enough to distinguish from list-style tools like search_console_pages or search_console_queries, though it does not explicitly name sibling alternatives.

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 gives clear usage context: use it to see whether performance is improving or worsening or whether a change had an effect. It also explains when to choose daily granularity. It stops short of naming alternative tools or explicit exclusions.

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