init_menstrual_cycle_setup

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

Annotations cover the safety profile (readOnlyHint=false, destructiveHint=false, openWorldHint=true), so the bar is lower. The description adds genuinely useful behavioral context the annotations don't: that tracking-preference settings are left untouched and that the tool presupposes an unconfigured account. It says nothing about effects on existing data or failure modes.

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 definition is a single compact clause pair with no filler, but it is front-loaded with a negative statement before any positive framing, which makes it read as a caveat with no antecedent. Brevity is fine; ordering is suboptimal.

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 3-required-parameter mutation with no output schema and 33% schema coverage, an agent needs at minimum what the tool creates and what the numeric parameters mean. The description supplies neither, covering only exclusions.

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 coverage is only 33% — periodStartDate documents its format, but cycleLength and periodLength carry no unit (days? entries?), range, or meaning anywhere. The description does not compensate at all, leaving two of three required parameters semantically opaque.

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 never states what the tool does — no verb+resource statement like 'initializes menstrual cycle tracking.' It only asserts exclusions ('does NOT also update tracking-preference settings', 'not intended for an already-configured account'), leaving the positive purpose to be inferred from the tool name alone.

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?

It does name an alternative for a related need (`updateMenstrualSettings`) and gives one negative precondition (not for an already-configured account), which implicitly defines when this tool IS appropriate. However, it never states the primary when-to-use condition, so guidance is implied rather than explicit.

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