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

Annotations already declare read-only, idempotent and open-world behavior, so the description correctly spends its words elsewhere: it discloses the credit cost, the data source (UniProtKB, UniProt Consortium), and that the returned sequence is the canonical one UniProt displays. The explicit negative scope (no variant, transcript, gene or DNA-derived output) is the kind of behavioral boundary annotations cannot express.

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 primary value (sequence ready for BLAST/alignment), then input form, source, exclusions, and cost in a single dense closing clause. No sentence is redundant; even the parenthetical cost is actionable.

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?

There is no output schema, yet the description covers the return format (plain text and FASTA plus length, organism, gene, evidence level), the input forms, the data source, and the limits. That is everything an agent needs to call it correctly and interpret the result.

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% and the schema already carries the accession example (P04637), the isoform form (P04637-2) and the protein_for_gene hint. The description restates those examples without adding format rules, edge cases, or error behavior, so it earns only the baseline.

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 and resource ('Get a protein's amino-acid sequence') plus the output form (plain text and FASTA) and provenance (UniProtKB). It clearly separates itself from protein_3d_structures and protein_for_gene by naming what it does not do (no DNA translation, no variants, no gene/mRNA sequences).

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?

Gives an explicit routing rule to a sibling ('use protein_for_gene to turn a gene symbol into an accession', repeated in the schema) and enumerates the adjacent tasks it should not be used for. An agent can decide correctness of invocation from the description alone.

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