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

Annotations already cover read-only, idempotent, non-destructive and the closed-world hint, so the description earns credit for adding non-obvious behavior: matching is "identical wording only" (a major semantic caveat), both sources are aligned over the same date window, and a Search Console property is required. It does not mention limits on result size or how unmatched terms are resolved, which keeps it short of a 5.

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 compact sentence plus two short clauses, front-loaded with the core comparison and the three output buckets. The trailing "Tools revision" string is noise, but the substantive text is dense with no filler.

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 no explanation, and the description sufficiently frames the comparison semantics. However, for a 5-parameter cross-source tool with 0% schema coverage, the unexplained site_url, days and detail parameters leave real gaps an agent must guess at.

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%, so the description must compensate for 5 undocumented parameters. It only vaguely gestures at the date window ("over the same dates"); it says nothing about days, the detail/ summary granularity, the render format, or — most importantly — that site_url selects the Search Console property to compare against.

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 (compare) and two named resources (Google Ads paid search terms vs Search Console organic rankings), then enumerates the three output categories it produces. This clearly differentiates it from siblings like analyze_search_terms or gsc_search_analytics, which operate on only one data source.

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 prerequisite "needs Search Console" and "over the same dates" imply the conditions for use, but no alternative tool is named and no exclusion is stated (e.g., when a plain Ads-only or GSC-only report suffices). Usage is inferable rather than explicit.

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