Pregnancy due date

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

Annotations already declare readOnly/idempotent/closed-world, so the safety profile is covered. The description adds valuable behavior beyond that: it lists what is returned (conception date, full-term date, weeks+days progress, trimester, days remaining, milestone timeline weeks 4–42, optional Hijri) and the disclaimer, though it stops short of describing response structure for the progress section.

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?

Dense but front-loaded: purpose first, then outputs, then the disclaimer and link. The enumerated output list is long but each item is informative; no filler sentences.

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?

With no output schema, the description fully carries the burden by enumerating every returned artifact and the optional Hijri expansion, plus a scope disclaimer. An agent can call this correctly without further documentation.

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 100%, so the baseline is 3; the description goes slightly beyond by naming Naegele's rule, the cycle-length range 20–45, and the day-3/day-5 embryo distinction, tying the parameters to their clinical meaning rather than just restating field names.

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?

States a specific verb+resource ('Estimated pregnancy due date') and enumerates the three accepted starting points (LMP, conception, IVF transfer), which clearly separates it from nearby siblings such as calc_age, calc_date_diff or calc_hijri.

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?

Explains which input method to pick and notes 'Estimate only, not medical advice,' which sets the appropriate use context. It does not explicitly name alternatives or exclusions (e.g., use calc_date_diff for plain date arithmetic), so it falls just short of a 5.

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