compare_periods

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

Annotations already declare readOnlyHint, idempotentHint, and non-destructive behavior, so the safety profile is covered. The description adds two useful behavioral facts — results are ordered by biggest movers and queries are matched across spellings — but says nothing about rate limits, result volume, or what happens when compare periods overlap.

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-loads the core purpose and ordering behavior, then moves into parameter enumeration with no filler. The dense inline lists are compact, though slightly cramped to parse.

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. However, for a 13-parameter analytical tool with zero schema coverage, the description leaves more than half the parameters unexplained and gives no guidance on level, search_type, or filter interactions.

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 13 parameters, so the description carries the full burden and only partly does so. It fully enumerates compare_to's four modes and dimension's five values (neither of which appears as an enum in the schema) and notes custom's prerequisite params — genuinely valuable — but days, level, limit, site_url, search_type, and the three filter params remain 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?

States a specific verb and resource ('Compare a period with an earlier one') plus an output-shape detail ('biggest movers first'), so the agent knows what it returns. It does not explicitly distinguish itself from the sibling history_compare, which likely covers similar ground, so it falls short of a 5.

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 real guidance on one decision point: compare_to values and the fact that 'custom' requires previous_start/previous_end. But it never says when to choose this tool over performance_overview, query_search_analytics, or history_compare, so usage is implied rather than directed.

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