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

Annotations already declare readOnlyHint, openWorldHint and destructiveHint=false, so safety is covered. The description adds useful behavioral context that the metrics are in the account currency and that results render 'as a card', but says nothing about latency, quota consumption on the live Google Ads API, pagination, or what happens when no ideas are found.

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?

A single front-loaded sentence that leads with what the tool produces, then the inputs, then the output shape. Dense but readable; 'Shown as a card' is the only bit that feels like UI plumbing rather than tool semantics.

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 an 8-parameter, all-optional tool with no output schema, the description carries the important context: that results include search volume, competition and bid range, and that they are scoped by location and language. The 'and/or' phrasing usefully signals that at least one of keywords or url is needed, though it omits any hint about the summary/full detail tradeoff.

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 all eight parameters are already documented in the schema and the baseline is 3. The description reinforces the keyword/URL sourcing and location/language scoping, but adds no syntax or defaults beyond what the schema states, and does not mention the 'detail' or 'limit' controls at all.

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?

Opens with a specific verb+resource ('Keyword Planner ideas') and names the exact inputs (seed keywords and/or a website URL) and the metrics returned (average monthly searches, competition, top-of-page bid range). This is clearly a research/discovery tool, distinguishable from sibling listing tools like google_ads_keywords or google_ads_search_terms, though those alternatives are never named so the boundary is inferred rather than stated.

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?

Usage is implied by the phrase 'Keyword Planner ideas' and the discovery framing, but there is no explicit when-to-use or when-not clause, and no sibling is referenced to route the agent (e.g. vs google_ads_find_topics or google_ads_keywords). An agent can infer this is for generating new keyword candidates, but must reason about the choice itself.

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