compare_periods

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It adds useful context about the tool's output ('Shows absolute and percentage changes') and data requirements ('Requires synced data'), but does not cover other behavioral aspects like error handling, performance characteristics, or authentication needs, leaving gaps for a tool with 8 parameters.

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?

The description is appropriately sized and front-loaded, with the first sentence stating the core functionality, followed by supporting details about output and prerequisites. Every sentence earns its place by adding distinct value without redundancy or fluff.

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?

Given the tool's complexity (8 parameters, no output schema, no annotations), the description is reasonably complete for a comparative analysis tool. It covers purpose, usage context, output format, and prerequisites, though it could benefit from more behavioral details or examples to fully compensate for the lack of annotations and output schema.

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 100%, so the schema already documents all parameters thoroughly. The description adds minimal value beyond the schema by implying the tool's purpose involves date ranges and dimensions, but does not provide additional syntax, format details, or usage examples for parameters beyond what the schema specifies.

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?

The description clearly states the tool's purpose with specific verbs ('compare two arbitrary date ranges side-by-side') and resources ('across any dimension'), distinguishing it from siblings like 'query_gsc_data' or 'get_insights' by focusing on comparative analysis rather than raw data retrieval or general insights.

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 provides clear context for when to use the tool ('before/after analysis, seasonal comparisons, or measuring the impact of changes') and includes a prerequisite ('Requires synced data — run setup first if needed'). However, it does not explicitly state when not to use it or name specific alternatives among the sibling tools.

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