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

Annotations already declare readOnlyHint=true, openWorldHint=true, destructiveHint=false, so the safety profile is covered. The description adds valuable context beyond that: data comes from live Keyword Planner (not cached), and it enumerates the metrics returned. It omits any note on quota/rate behavior of the Ads API, which keeps it below 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?

A single tight sentence with the resource, source, and returned metrics front-loaded; no filler or repetition of structured fields.

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 zero required parameters and no output schema, the description usefully previews the return fields (searches, competition, CPC), which is what an agent most needs. It does not state that at least one of keywords/url must be supplied, a minor gap for a 6-param tool.

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 schema already documents all six parameters including defaults. The description only reinforces the keywords/url duality ('and/or'), adding nothing about format or the mutual-optionality constraint beyond what the schema states.

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 and resource ('Research keywords via Google Keyword Planner') and names the concrete data returned: average monthly searches, competition, top-of-page CPC. It is clearly distinct from write-side siblings like google_ads_add_keywords, though it never names an alternative explicitly.

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 only implied: the description says it works 'for seed keywords and/or a page URL,' which signals the two input modes but not when to pick this over google_ads_query or google_ads_insights. No exclusions or preconditions are stated.

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