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

With no annotations, the description carries the full burden and does disclose two useful behavioral facts: the auth/connection requirement and the growth-ranking basis (breakout, rising, largest). It says nothing about return shape, volume of results, or rate/limits, and the stated 'last quarter' basis sits oddly against a schema default of PAST_7_DAYS.

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?

Two compact sentences, front-loaded with the core purpose and ending with the prerequisite. The parenthetical '(breakout, rising, largest)' is terse enough to be slightly ambiguous, but nothing is padded or wasted.

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 research tool with no annotations and no output schema, the description is thin: it never clarifies what the result set looks like or how it differs from the several sibling keyword-research tools. An agent has to guess which of the keyword-research siblings to invoke.

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 coverage is 67%, so the schema documents region and category but leaves the timeframe enum unexplained. The description adds the ranking dimensions but its 'over the last quarter' wording conflicts with the schema's PAST_7_DAYS default rather than clarifying which enum values mean what, so it only partially compensates.

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 — Keyword Planner keyword ideas for a category, ranked by search-volume growth — so the agent knows this is a trend-discovery research tool. It does not, however, distinguish itself from the adjacent sibling google_ads_get_keyword_research, which appears to serve a similar research purpose.

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 provides one prerequisite ('Needs the customer's Google Ads connection'), which is real context for calling it. But it never says when to prefer this over google_ads_get_keyword_research or get_keyword_research, nor any exclusion, so usage is only implied.

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