ensembl_homologs

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

No annotations are provided, so the description carries full responsibility for behavioral disclosure. It states the data source (Ensembl Compara) and the return fields, which gives a basic sense of behavior. However, it does not mention any rate limits, authentication requirements, error handling, or whether the operation is read-only (although that's implied). This is adequate but not rich, hence a 3.

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 description is brief and the key action is front-loaded. However, it redundantly repeats the same information in both English and Chinese, which adds no value for an AI agent and could be seen as unnecessary verbosity. Still, it's compact and sets the scope early, so a 4 is fair.

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 details are covered by that. However, the description omits any explanation of the parameters, which is critical given the schema has no descriptions. It also does not differentiate itself from sibling tools. For a simple query tool it's mostly sufficient, but the missing parameter guidance and lack of when-not-to-use leave it incomplete.

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?

The schema provides zero descriptions for the three parameters (symbol, species, target_species), and the description does not compensate. It mentions returning species and homolog IDs, but never explains that 'symbol' is the query gene, 'species' is the source organism, or 'target_species' is the comparison set. Given 0% schema coverage, the description must clarify parameter semantics and fails to do so.

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 clearly states the action ('Query homologous genes (orthologs/paralogs)') and the specific resource ('Ensembl Compara'), and mentions the returned data (species, homolog ID, sequence identity). This unambiguously distinguishes it from other gene-related tools like ensembl_gene_lookup, which focus on gene details rather than homologs.

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?

The description provides clear context on when to use this tool: 'for evolutionary analysis and model organisms.' It does not explicitly state when NOT to use it or name alternative tools, but the intended use case is implicit from the phrasing. Since it lacks explicit exclusions or sibling comparisons, a score of 4 is appropriate.

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