BabyData pregnancy calculators

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

With no annotations provided, the description carries the full burden and does well by naming the calculation rule, listing the returned values, and stating that it is informational only and not medical advice. It could still be stronger by mentioning assumptions or validation behavior, but the core behavioral profile is clear.

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 sentences and front-loads the core purpose, method, and output summary before the disclaimer. Every sentence adds useful information with no repetition.

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?

There is no output schema, so the description appropriately enumerates the key return values: estimated due date, weeks pregnant now, trimester, and weeks remaining. It also covers input methods and includes the necessary informational-only disclaimer, making it complete for an agent to call correctly.

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 parameter descriptions already define date, method, asOf, and embryoAge. The tool description adds context by naming the three supported dating approaches, but it does not add meaning beyond the schema for asOf or embryoAge, so the baseline 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 states a specific verb and resource: estimate a pregnancy due date and current stage using named dating methods. It is clear what the tool computes, but it does not explicitly distinguish itself from the sibling tool pregnancy_weeks, which likely overlaps with the 'weeks pregnant now' output.

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?

Usage is implied by the listed dating methods (LMP, conception, IVF transfer), but there is no explicit guidance on when to choose this tool over calculate_ovulation or pregnancy_weeks. The medical disclaimer helps set context but does not route the agent between alternatives.

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

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

With no annotations, the description must carry the full behavioral burden. It does convey that the tool is purely informational (no side effects) and that results are estimates ('likely'), but it omits assumptions about cycle regularity, precision, and output format, leaving meaningful gaps.

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?

Two sentences, front-loaded with the purpose and followed by a terse disclaimer. Every sentence earns its place with no redundancy.

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 simple two-parameter calculator with no output schema, the description adequately states what will be returned and includes a safety disclaimer. Minor gaps remain around underlying assumptions (e.g., regular cycles) and output date formatting.

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 both parameters are fully documented in the schema. The description merely restates the inputs ('first day of the last period and the average cycle length') without adding syntax, range, or format details beyond what the schema already provides.

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 uses a specific verb ('Estimate') and names three concrete outputs (ovulation day, fertile window, next period), which clearly differentiates it from sibling calculators like calculate_due_date or pregnancy_weeks.

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?

No guidance is given on when to use this tool versus alternatives, nor any prerequisites or exclusions. 'Informational only' is a disclaimer, not usage guidance, so the agent must infer the context from the inputs alone.

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

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

With no annotations, the description carries the disclosure burden and does reasonably well: it explains the calculation method (90% for 6 weeks, then lower of flat rate or 90%), pins the rate to a specific tax year (£194.32 for 2026-27) and warns it changes each April. The 'estimate only, not advice' caveat is a valuable editorial trait. It stops short of saying what happens if both earnings inputs are omitted, which matters given zero required parameters.

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?

Front-loaded with the core purpose before the rate detail, and every clause carries information. The rate figure and the April-change warning are slightly heavy for a one-liner but are genuinely useful, so waste is minimal.

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?

No annotations and no output schema, so the description must explain the computation and the disclaimer, and it does. The remaining gap is the optional-parameter story — nothing tells the agent what the tool does when neither annualSalary nor weeklyEarnings is provided.

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 description coverage is 100%, so both parameters are already documented, and the baseline is 3. The description's phrase 'average weekly earnings' loosely mirrors weeklyEarnings but adds no syntax, units beyond GBP, or guidance on how annualSalary vs weeklyEarnings interact when both are supplied.

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 and resource — 'Estimate UK Statutory Maternity Pay' — with the scope nailed down to the 39 weeks and gov.uk rules. It is immediately distinguishable from the siblings (due date, ovulation, pregnancy weeks), none of which touch pay calculation.

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 domain is clear enough that an agent can infer when to reach for it, and 'Estimate only, not advice' sets a boundary on how to present results. However, there is no explicit statement of when NOT to use it or what alternative exists for related pay questions, so guidance is implied rather than stated.

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

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

No annotations are provided, so the description carries the whole burden. It usefully discloses scope limits ('Informational only, not medical advice') and the calculation basis via the schema's 280-day back-calculation. However, it never says what happens when neither optional input is supplied or when both lmp and dueDate are given, which is a real ambiguity for a tool with zero required parameters.

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?

Two sentences, front-loaded with the computation and its outputs, followed by the scope disclaimer. No filler, and the disclaimer earns its place in a medical-adjacent context.

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 and no annotations, the description does the important work of naming what is returned (weeks/days, trimester, progress). The remaining gap is input-selection behavior when zero or two date inputs are supplied, which matters given that all three parameters are optional.

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 description coverage is 100%, so the baseline is 3, but the description adds something the schema does not: that LMP and due date are alternative entry points rather than complementary inputs. It still does not resolve precedence when both are supplied, so it does not reach 5.

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 ('work out') and a precisely enumerated result set: weeks and days pregnant, the trimester, and progress through the 40 weeks. The 'from either the LMP or the due date' clause implicitly distinguishes it from sibling calculate_due_date, which runs the conversion the other way.

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 says it can be driven from LMP or due date, which is mild usage guidance, but never states when to pick this tool over calculate_due_date, calculate_ovulation, or the other siblings. There is no explicit alternative routing or when-not-to-use condition.

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