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

Annotations already declare readOnlyHint=true, openWorldHint=true and destructiveHint=false, so the safety profile is covered. The description adds real value beyond that: the date range is "frozen," nullable fields preserve missing evidence, and estimates explicitly do not represent actual account performance. That is meaningful caveat context, though the return shape/pagination is not described.

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?

Three short sentences, front-loaded with the core purpose, with no filler. The disclaimer sentences are compact, though "No additional calls or fallback" is slightly cryptic about what it actually constrains.

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?

No output schema exists and parameter coverage is 0%, so the description should carry more weight than it does. It covers the forecast horizon and null-handling caveat but omits the return structure, bid/match semantics, and size limits an agent needs 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 description coverage is 0%, so the description must carry parameter meaning, but it only gestures at keywords, date range and spend/CPC. It never explains bidUsd (constrained 1-100), the match enum (EXACT/PHRASE/BROAD) semantics, or the 20-keyword cap, leaving four required parameters largely undocumented.

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 names a specific verb and resource: Google Ads keyword click, CPC and spend forecasts. This is clearly distinguishable from most siblings (image/video/patent tools), though it doesn't explicitly contrast with near-neighbours like nexscope_seo_target_traffic_estimates or nexscope_seo_ad_audience_estimate. Purpose is clear but sibling differentiation is left to inference.

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?

"Over a frozen future date range" and "no additional calls or fallback" imply when this tool applies (forward-looking forecast, single-shot), but there is no explicit when-to-use/when-not or pointer to the alternative forecast tools. Usage is implied rather than stated.

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