compare_search_periods

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

Annotations already cover readOnly/idempotent/non-destructive, so the description's added value is the delta-sign semantics (positive = Period 1 improved, including the inverted case of lower position being better) and the fact that filters apply to both periods. Useful behavioral context beyond structured fields, though it says nothing about pagination or how many dimensions are returned.

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?

Front-loaded with the core comparison semantics and the sign convention before the Args block, and every line of that block conveys non-obvious information. No restatement of the tool name or filler prose.

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 nine-parameter comparison tool with an output schema already describing return values, the description supplies everything needed to invoke it correctly: period roles, defaults, formats, and filter behavior.

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 carries the full burden and largely succeeds: it documents all nine parameters, their date format (YYYY-MM-DD), search_type values, dimensions syntax ('query,page'), and the limit default of 20. The one gap is the filters parameter, whose accepted shape (string vs object vs array) is never clarified.

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 (compare two date ranges item by item) and names the entities being compared (queries, pages). It is clearly distinguishable from sibling analytics tools like get_search_analytics and get_performance_overview because it is explicitly a period-over-period comparison.

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?

Explains the directional convention (Period 1 analysed vs Period 2 baseline) and the no-argument default (last 28 days vs the preceding 28 days), which is exactly the usage context an agent needs. It does not name an alternative tool or state when not to use a comparison, so it falls short of a 5.

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