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

Annotations already declare the read-only, idempotent, non-destructive safety profile. The description adds useful detail about returned data (gene/name, alleles, effect, frequency, sources) but does not reveal edge behavior such as unknown-rsID handling.

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?

One compact, front-loaded sentence carries the tool's scope and return contents with no filler or repeated structured data. It is efficient and easy to scan.

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 single-parameter read-only lookup with no output schema, the description adequately communicates the input and the main categories of returned information. Nothing needed to select or invoke the tool correctly 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 fully documents the single required parameter, including an example format, so the description need not add param-level detail. The mention of dbSNP rsID in the description merely reinforces the schema.

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 lookup verb and resource ('One variant by dbSNP rsID') and enumerates what is returned, so an agent can tell it apart from gene-listing and gene-lookup siblings. It is not a tautology and carries concrete scope.

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 clearly conveys the selection criterion: use this for exactly one variant identified by a dbSNP rsID. It stops short of naming sibling alternatives or explicit when-not conditions, but the context is unambiguous.

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