Compare periods

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

The description adds behavioral context beyond the readOnlyHint annotation by detailing the output (per-metric change, percent change, improved/declined/unchanged assessment). No contradiction with annotations; readOnlyHint is consistent with a read-only comparison operation.

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 two concise paragraphs. The first paragraph states purpose and output, the second explains date format and usage. No unnecessary words; every sentence adds value. Front-loaded with key information.

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 complexity of 4 required string parameters with flexible date formats and the presence of an output schema, the description provides sufficient context: it explains the date format variety, the baseline logic, and the metrics covered. No gaps for an AI agent to correctly invoke the tool.

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?

The input schema has 0% description coverage, but the description explains that all four parameters accept the same flexible date expressions (e.g., 'today', 'yesterday', 'last week') and provides an example. This adds significant meaning beyond the bare schema, though per-parameter specifics could be more explicit.

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 compares two date ranges across specific health metrics and provides per-metric change, percent change, and an assessment. This distinguishes it from sibling tools like 'get_daily_summary' and 'get_health_overview' which do not perform comparisons.

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 explains that Period A is the baseline and Period B is compared against it, and provides examples of acceptable date expressions (e.g., 'last week', 'YYYY-MM-DD') and a usage example ('compare last month to this month'). It does not explicitly mention when not to use or compare to alternative tools, but the guidance is clear for typical use.

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