get_performance_overview

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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so safety is covered. The description adds real value by revealing that site_url falls back to the GSC_SITE_URL environment variable and that days defaults to 28, but it says nothing about data freshness/lag, rate limits, or what happens on an invalid 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?

One summary line up front followed by a compact Args block; every line carries information and nothing is padded.

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?

An output schema exists, so return values need not be explained, and all three optional parameters are documented. However, for a tool sitting among ten-plus analytics siblings, the description never positions it in that family or notes GSC's typical reporting lag, both of which an agent needs to call it in the right situation.

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 0% and there are no enums in the schema, so the description must carry the burden — and it does: it explains the environment-variable fallback for site_url, the meaning of days as a lookback window, and the six valid search_type values. It stops short of clarifying the required site_url format (e.g., sc-domain vs URL-prefix properties).

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 first sentence names the exact metrics returned (clicks, impressions, CTR, position) plus the day-by-day trend, so the resource and output shape are clear. It does not differentiate itself from closely related siblings such as get_search_analytics, get_advanced_search_analytics, or compare_search_periods, leaving the agent to infer which to pick.

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?

There is no statement of when to use this tool versus the many analytics siblings, and no exclusions. The Args block supplies defaults but is purely mechanical parameter listing, not usage guidance.

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