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

No annotations are provided, so the description carries the full behavioral burden. It enumerates the metrics returned but says nothing about permissions, rate limits, whether results are cached, or the seed-keyword requirement, so transparency is thin for a research tool.

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 lists the concrete outputs with no filler. Efficient, though the metric list is dense enough that it borders on enumerating return values rather than explaining the tool's role.

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 no-annotation, no-output-schema read tool, the description partly compensates by naming the returned metrics, but it omits usage context and sibling differentiation. Adequate but with clear gaps an agent would need to resolve to call it correctly.

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 75%, so most parameters are documented in the schema itself. The description only loosely maps to them ('customer and competitor keywords' hints at seedKeywords and competitorDomains) and adds no format or syntax detail; includeSearchVolume is undocumented in both places. Baseline 3 applies.

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 clear verb ('Discover') plus the resource and the specific data returned (keywords, search volume, CPC bids, competition index, competitor auction share). However, it does not distinguish itself from closely related siblings like google_ads_discover_trending_keywords or google_ads_get_social_keywords, leaving the agent to infer which keyword tool to pick.

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?

There is no when-to-use or when-not-to-use guidance, and no alternatives are named. With siblings like google_ads_discover_trending_keywords and google_ads_get_social_keywords in the same family, the absence of routing guidance is a real gap.

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