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

Annotations already cover the safety profile (readOnly, idempotent, openWorld), and the description adds real operational context beyond them: 5,000-row cap with startRow paging, ctr expressed as a fraction, and roughly 2-day data lag. It does not mention quota or error behavior, but the freshness and paging details are exactly the kind of trait annotations cannot express.

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 purpose and metrics are front-loaded, and the later sentences (paging, ctr scale, data lag) each carry a concrete fact. It is a dense run-on, and the enumerated dimension/search-type lists duplicate the schema enums, which is mild waste but also aids routing.

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?

With 10 optional parameters and no output schema, the description carries the return-shape burden itself by naming the returned metrics, and it covers freshness, paging, row caps, and the ctr scale. An agent has everything needed to call this correctly and interpret the response.

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 baseline is 3 and the schema already documents defaults, enums, and constraints. The description largely restates schema facts (5,000 row max, startRow paging, hour/dataState coupling, 2-day-default endDate); only the ctr-as-fraction note is genuinely new semantic guidance.

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+resource: it returns the Search Console performance report with named metrics (clicks, impressions, ctr, average position) and the exact dimensions and search types it can break down by. An agent can distinguish this from search/inspection siblings such as gsc_inspect_url without opening a 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?

The description gives a strong usage clause: "Use this for any analysis of the customer's own Search Console data" followed by concrete scenarios (top queries, top pages, branded vs non-branded, regex filters). It does not explicitly name or exclude the closest alternatives (gsc_inspect_url for single-URL inspection, gsc_properties for listing properties), so routing still requires some inference.

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