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.