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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so the safety profile is covered. The description adds substantive behavior beyond that: it preserves conflicting and limited assertions, returns inheritance and snapshot provenance, and clarifies scope limits (not variant pathogenicity, not a diagnosis, requires professional review).

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 action, followed by return contents and scope limitations in compact sentences. It is slightly long at five sentences, but each carries a distinct point (scope, inputs, outputs, disclaimers), so little is wasted.

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?

An output schema exists, so return-value detail is not strictly required, yet the description still usefully characterizes the payload and its caveats. Combined with the scope-boundary disclaimers, an agent has enough to invoke it correctly, with only alternative-tool routing 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?

Schema coverage is 100%, so the schema already documents gene, limit, and offset. The description restates the accepted identifier format ('exact gene symbol or HGNC identifier') without adding syntax, constraints, or pagination semantics beyond the schema; baseline 3 applies.

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 (Find) and resource (diseases associated with a human gene), clearly scoping the direction of the query as gene→disease. It does not explicitly name the reverse sibling (search_disease_genes), so an agent must infer the direction, but the scope 'one human gene' is unambiguous.

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 research context (bioinformatics and clinical genomics) and constraints ('use only a public gene identifier; no patient or case data'), which implies when the tool applies. However, it never names search_disease_genes or any alternative, nor states when to prefer this over the reverse lookup, so routing is left to inference.

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