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

Annotations already declare read-only, idempotent, non-destructive behavior; the description adds the important constraint never to send the user's genotype and lists what the lookup returns. It does not discuss rate limits or error behavior, but given annotation coverage this is solid.

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?

Three compact sentences: return scope first, input/privacy constraint second, scope limit third. No filler, and critical constraints are front-loaded.

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 one-parameter read-only lookup with no output schema, the description gives enough return-field detail, input constraint, and scope caveat for an agent to call it correctly. Nothing essential is missing.

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?

The schema already documents the rsID parameter with an example, and the description reinforces that only the rsID should be sent—never genotype. That adds meaningful privacy and semantic guidance beyond the schema's type description.

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 that the tool returns one variant identified by dbSNP rsID and enumerates the fields returned, so the resource and scope are clear. It also distinguishes the output from phenotype/metabolizer status, though it does not explicitly name sibling tools such as lookup_gene.

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?

Provides clear usage context (one variant, rsID input) and a key exclusion (not a phenotype or metabolizer status), plus the privacy constraint to send rsID only. It stops short of explicitly naming alternative sibling tools for phenotype or gene-level questions.

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