Menstrual cycle

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so the description need not repeat them. It adds substantial context: data sensitivity and on-device storage, the meaning of coverage fields, and the pitfall of misinterpreting limit-shaped windows. This goes well beyond annotations, making the tool's behavior very transparent.

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 relatively long but densely packed with useful information. It is structured into clear paragraphs: purpose, sensitivity, and coverage instructions. The front-loading of purpose and the use of the 🔴 emoji to flag a critical warning are effective, though the length could be trimmed slightly without losing value.

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 that an output schema exists to document return values, the description focuses on what the schema cannot convey: sensitivity, coverage interpretation, and the limit pitfall. It covers all major behaviors an agent needs to call the tool correctly, including how to handle partial history. Nothing critical is missing.

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?

With schema description coverage at 0%, the description must explain parameters. It clarifies `owner` (filter by person) and `limit` (controls how many days are fetched, and interacts with `more_available`). However, it never mentions the `fresh` parameter, leaving it unexplained. This is a notable gap, so a score of 3 is appropriate.

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 opens with 'Decrypt recent menstrual cycle data locally and predict the next period,' which clearly states a specific action and resource. It also mentions returning recent samples plus a prediction, distinguishing it from sibling get_* tools like get_weight_trend or get_sleep_detail. The purpose is unambiguous and unique.

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 explicit guidance on using the `owner` prefix for filtering and explains how `limit` affects coverage with `more_available`. It does not explicitly state when to use this tool versus alternatives, but the unique domain makes that implied. It offers clear instructions on handling the coverage block, which is more than minimal.

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