STRING: Retrieve proteins associated with a functional term

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

No annotations are present, so the description carries the full burden, and it does meaningful work: it discloses the single-species limitation (and that it cannot rank species by protein count), warns that results reflect annotation depth and should be interpreted cautiously, and offers a query-simplification fallback. It does not mention permissions, rate limits, or read-only status, but for a retrieval tool these matter less than the interpretation caveats it does provide.

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?

The usage guidance is front-loaded and well-organized, but the description ends with an enumeration of output fields (category, term, description, proteinCount, preferredNames, etc.) that duplicates what the existing output schema already declares, adding length without new value. Removing that block would make it tighter and more focused.

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?

With an output schema present, the return values are covered, and the description supplies the remaining context an agent needs: species constraint, term-format conventions, interpretation caveats, and a no-results fallback. It is nearly complete; the only real gap is the absence of any pointer to competing sibling tools for related tasks like enrichment.

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 baseline is 3; the description goes beyond the schema by giving real guidance on how to format term_text (BRENDA tissue nomenclature, omit the word 'tissue'), which is not stated in the schema. That extra syntax/format guidance lifts it above baseline, though it does not clarify detail_for_term's interaction with the omitted fields beyond what the schema already says.

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 ('Retrieve proteins annotated with a functional term or descriptive text') plus an explicit scope constraint ('in a single species'), and enumerates the queryable categories (tissues, compartments, diseases, processes, pathways, domains). It is clear what the tool does, but it never names a sibling (e.g. string_enrichment or string_functional_annotation) to disambiguate, so it falls short of a 5.

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 concrete usage context: the categories you can query, the warning to run the tool separately per species for cross-species comparisons, and a fallback ('If no results are found, try simplifying the query'). It also supplies a domain convention for tissue queries (BRENDA nomenclature, omit the word 'tissue'). No explicit 'do not use this when…' or named alternative is given, so it is a strong 4 rather than a 5.

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