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

Annotations already declare readOnlyHint=true, openWorldHint=true, and destructiveHint=false, so safety is covered. The description adds the comparison semantics (click drop versus prior period), which is genuine context beyond the annotations, but it does not mention that results are gated by min_impressions_previous, what window 'prior period' uses, or truncation via row_limit.

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 with no filler, which is good, but it is under-specified rather than economical for a 6-parameter analytical tool. Nothing is wasted, yet too little is said.

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?

An output schema exists, so return values need not be explained, but the tool's complexity (comparison windows, dimension choice, impression floor, row cap) is not addressed at all. An agent could not confidently set four of the six parameters from this definition.

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% across 6 parameters, so the description must carry the load and does not. Only decline_threshold_pct is referenced, and even that only by name; days, dimension, min_impressions_previous, row_limit, and site_url are left entirely to the bare schema types and defaults.

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: finding pages or queries whose clicks dropped by at least decline_threshold_pct versus the prior period. That makes it distinguishable from siblings like find_dead_pages, find_new_pages, and find_quick_wins, though it never names those alternatives 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?

The description gives no guidance on when to choose this over find_dead_pages, find_new_pages, or compare_periods, nor any prerequisites for the comparison window. The agent must infer selection criteria from the sibling list alone.

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