lookup_gene_by_symbol

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

With no annotations provided, the description carries full burden for behavioral disclosure. It mentions the tool returns 'detailed information' but doesn't specify format, structure, or potential limitations (e.g., rate limits, authentication needs, what happens if the gene isn't found). For a lookup tool with zero annotation coverage, this leaves significant behavioral questions unanswered.

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 appropriately concise - a single sentence that states the core functionality. It's front-loaded with the main purpose and includes useful examples. However, it could be slightly more structured by separating the lookup action from the return information for better clarity.

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?

Given no annotations and no output schema, the description is incomplete for a lookup tool. It doesn't explain what format the 'detailed information' returns, doesn't mention error conditions or edge cases, and provides minimal behavioral context. For a tool that presumably returns structured gene data, this leaves too much unspecified for the agent to use it effectively.

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 already fully documents all three parameters. The description adds minimal value beyond the schema - it provides an example (BRCA2) for the symbol parameter but doesn't explain parameter interactions or provide additional context about species selection or expansion behavior. Baseline 3 is appropriate when schema does the heavy lifting.

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 tool's purpose: 'Look up a gene by its symbol' with specific examples (BRCA2) and mentions the type of information returned (ID, location, description). It distinguishes from siblings like 'lookup_gene_by_id' by specifying the lookup method (symbol vs. ID). However, it doesn't explicitly differentiate from 'get_xrefs_by_symbol' which might be a similar lookup tool.

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 no guidance on when to use this tool versus alternatives. It doesn't mention when to choose this over 'lookup_gene_by_id' or 'get_xrefs_by_symbol', nor does it provide any context about prerequisites, limitations, or typical use cases. The agent must infer usage from the tool name alone.

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