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

Beyond the readOnly/idempotent annotations, the description discloses that it returns only the top reviewed match, that species defaults to human (9606), that TrEMBL/unreviewed entries are excluded, the source (UniProtKB), and a cost of 1 credit. These are meaningful behavioral constraints an agent couldn't infer from annotations alone. Minor gap: no mention of behavior when the symbol has no reviewed match.

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 mapping and return fields, followed by usage context, constraints, and source/cost. Slightly dense with parenthetical asides (example, cost), but every sentence carries information relevant to invoking the tool correctly.

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 2-parameter lookup with no output schema, the description covers purpose, source, filtering rules, defaults, and return fields. The main omission is failure behavior (no reviewed match, multiple species) and output format specifics, but overall it is sufficient for an agent to call it correctly.

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 both parameters (symbol, organism) are already documented in the schema, including examples and the default 9606. The description reinforces species defaulting and gives a gene-symbol example, but adds no format details beyond the schema. Baseline 3 is appropriate.

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 verb and resource ('Map a gene symbol to its expert-reviewed protein') and enumerates the returned fields (accession, entry name, protein name, synonyms, length, function summary). The worked example (TP53 to P04637) makes the transformation unambiguous and distinguishes it from siblings like protein_sequence or protein_3d_structures.

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?

It frames the tool as 'the standard gene-to-protein step for bioinformatics pipelines and coursework,' which gives clear context on when to reach for it. It also states the species scope and that only reviewed Swiss-Prot entries are considered. It doesn't explicitly name an alternative sibling or state when not to use it, so it falls short of a 5.

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