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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered; the description still adds genuinely new behavior: volumes are cached for 30 days and force_refresh re-measures, and the result flags zero-demand keywords and names a better keyword from the page's suggestions. It does not mention cost/quota implications of a forced refresh, which would have pushed this to 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?

Three tight sentences, front-loaded with the core measurement and followed by the flagging behavior and the cache/refresh caveat. 'Changes no page' slightly restates readOnlyHint but works as a one-clause reassurance; no filler otherwise.

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 no output schema, the description carries the burden of explaining returns, and it does so at a conceptual level (per-page demand, a 'none' flag, a suggested better keyword). It stops short of describing result shape or what happens for pages with no keyword at all, a minor gap for a 4-parameter read 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 coverage is 100%, so baseline is 3, but the description adds real semantics: `keywords` are *extra* terms measured on top of each page's primary keyword (a distinction the schema's 'candidates you are weighing' only partly conveys), site_id determines the country whose Google volumes are used, and force_refresh is framed as bypassing the 30-day cache.

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+resource: measures monthly Google search volume for each page's primary keyword plus any extra keywords, scoped to the site's country. This is clearly distinguishable from siblings like suggest_keywords (which proposes terms) or get_growth_dashboard (which aggregates). The parenthetical about demand "none" makes the output concept concrete.

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?

The description implies the use case (audit whether target keywords have measurable demand before optimising a page) and notes it 'Changes no page,' but never states when to call it versus suggest_keywords or update_page_seo, nor any precondition beyond site_id. Usage is inferable rather than explicit.

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