lookup_gene_by_id

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

With no annotations provided, the description carries full burden but only states the basic lookup function. It doesn't disclose behavioral traits like whether this is a read-only operation, what data is returned, error conditions, rate limits, or authentication requirements. The description is minimal beyond the basic purpose.

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?

Single sentence with zero waste - every word contributes essential information. Front-loaded with the core purpose, followed by specific identifier details and example. Perfectly sized for this simple lookup 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?

For a tool with no annotations and no output schema, the description is too minimal. It doesn't explain what information is returned about the gene, whether the lookup is case-sensitive, what happens with invalid IDs, or how the 'expand' parameter affects results. The description should provide more context given the lack of structured metadata.

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 the schema fully documents both parameters. The description mentions the 'id' parameter with an example but doesn't add meaning beyond what the schema provides. No credit for repeating schema information, but no penalty since schema coverage is complete.

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 ('Look up') and resource ('a gene'), specifies the identifier type ('Ensembl stable ID'), and provides a concrete example. It distinguishes from sibling tools like 'lookup_gene_by_symbol' by specifying ID-based lookup rather than symbol-based.

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 implies usage when you have an Ensembl stable ID, but doesn't explicitly state when to use this vs. alternatives like 'lookup_gene_by_symbol' or 'get_xrefs_by_gene'. It provides context for the input but lacks explicit guidance on tool selection.

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