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

Annotations already mark the tool as read-only, idempotent, and non-destructive. The description adds meaningful behavioral context: values are not stored or logged, it is educational not diagnostic, and the user's own report range takes precedence. This exceeds the annotation-only information without contradicting it.

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 compact and front-loaded with the core action, followed by output details and caveats. It is slightly dense but every clause adds information; no filler or 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?

Given there is no output schema, the description does a good job enumerating what the user receives: flags, interpretation copy, retest guidance, citations, and links. It omits edge-case behavior like missing markers or ambiguous units, but these are not critical for a safe, stateless interpretation tool.

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 only 20%, and the description does not adequately compensate. It mentions 'sex- and age-specific bands,' which hints at the age and sex parameters, but pregnancy and postmenopausal are not explained anywhere. The values parameter is only minimally described via the schema example.

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 a specific action ('Flag each pasted lab value as low / normal / high') and a specific resource (TestWell's physician-reviewed reference catalog). It also distinguishes itself from siblings like lookup_reference_range by focusing on interpretation and flagging rather than just returning ranges.

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 when to use it — when a user has lab values to interpret — but does not explicitly contrast it with alternatives such as lookup_reference_range or convert_units. It gives a clear context but no exclusions or when-not-to-use guidance.

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