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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety profile is covered. The description adds valuable behavioral context: pricing ($0.002 USDC per successful call via x402), failed calls are not charged, and human-only scope (taxon 9606).

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-loads the core resource and scope, then adds constraints and pricing without waste. Every sentence carries useful information for an agent deciding whether and how to call the tool.

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 a simple two-parameter lookup with full schema coverage, annotations, and an output schema, the description covers the key remaining context: human-only scope, reviewed Swiss-Prot source, max entries, cost, and failed-call billing behavior.

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 100%, so both parameters are already documented in the schema. The description reinforces that the input is a gene symbol and notes up to 5 entries per call, but adds little beyond the schema's own parameter descriptions.

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/resource: UniProt reviewed Swiss-Prot human protein entries for a gene symbol, and lists the returned fields (accession, protein name, gene, sequence length, function summary). It clearly distinguishes this from sibling tools like STRING protein networks or KEGG pathway genes.

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?

Implies usage for retrieving human protein entries by gene symbol and gives constraints (human only, up to 5 entries), but it does not explicitly say when to use this tool versus related siblings such as health_string_protein_networks or health_kegg_pathway_genes.

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