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

Annotations already declare readOnlyHint=true, destructiveHint=false, openWorldHint=true, so the safety profile is covered. The description adds genuinely new behavioral context: scores are relative (not absolute volumes), zero is a sentinel for insufficient data, replay retains frozen provider dates, and interpolation is disallowed — all things the annotations cannot convey.

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 what the tool returns, followed by two compact constraints. No filler, though 'Preserve provider dates and do not interpolate search volumes' is terse enough to be slightly ambiguous about what exactly is being preserved.

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 does partial duty by explaining that return values are relative-interest scores with zero as a no-data sentinel. It stops short of describing the response shape (date/score series) or pagination, but for a simple 4-param read tool with full annotations, an agent has enough to call and interpret it.

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 50%: the date bounds and keyword item constraints are documented in-schema, while the keywords array itself and market lack descriptions (market is pinned by const/default 'US'). The description contributes the US scope and the 'don't rewrite provider dates' rule for dateTo, but adds nothing about the 1–5 keyword limit.

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 ('relative interest history') and pins the market to the United States, which separates it from broader siblings like nexscope_seo_keyword_history and nexscope_google_trends_by_keywords. It doesn't explicitly name which sibling to use for regional or demographic breakdowns, so an agent still needs to infer the boundary from names alone.

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 usage (trend/interest-over-time queries in the US) and gives handling rules for the data ('preserve provider dates', 'do not interpolate'). But it never says when to prefer it over nexscope_seo_keyword_interest_regions, nexscope_seo_keyword_interest_demographics, or the Google Trends siblings, and gives no exclusions.

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