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

Annotations already provide readOnlyHint, idempotentHint, and destructiveHint, so safety is well covered. The description adds meaningful behavioral context beyond annotations: period bounds use the user timezone, history dates are formatted YYYY-MM-DD, and secrets are intentionally omitted. This level of additional detail is appropriate for annotations that already cover the operational profile.

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?

Three sentences, no filler, and the core purpose is front-loaded in the first clause. Every sentence earns its place: what it returns, timezone behavior, date format, and negative scope. This is a model of concise, effective tool documentation.

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 zero-parameter read tool with a full output schema and annotations covering safety, the description is complete. It adds the only contextual details an agent might need beyond structured data: timezone semantics, date format, and the absence of secrets. Nothing essential 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?

The tool has zero parameters and the schema coverage is vacuously 100%, so there is nothing for the description to add about parameter meaning. The description correctly stays silent on parameters rather than inventing unnecessary detail. Per the baseline for a 0-parameter tool, this is well handled.

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 gets menstrual-cycle periods, settings, and history for the authenticated user. This specific verb+resource combination distinguishes it from sibling tools like get_me, get_notes, and get_holidays. The scope is further tightened by the explicit exclusion of cycle-share links and secrets.

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 implies this is the read operation for menstrual-cycle data, contrasted with write siblings like save_flow and delete_flow. However, it does not explicitly state when to choose this over alternatives or mention any exclusion conditions. The negative scope hint is useful but does not fully replace explicit when-to-use guidance.

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