rcsb_get_chem_comps

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

Beyond the annotations (readOnly, idempotent, etc.), the description discloses useful behavior: unknown IDs are returned under 'not_found' and default fields are curated. This adds context about response behavior and field customization, though it doesn't cover all possible behaviors (e.g., rate limits).

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 concise and well-structured. The first sentence states the core function, followed by default fields and parameter details. Every sentence adds value, with no filler or repetition.

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?

The description is complete for this tool's complexity. It provides the input format, parameter semantics, default behavior, and points to an auxiliary tool for field discovery. The presence of an output schema covers return value details, so nothing essential is missing.

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?

Despite 0% schema description coverage, the description thoroughly explains both parameters: comp_ids as short codes with example and not_found behavior, and fields as an optional GraphQL selection with a specific example and a pointer to discover valid paths. This fully compensates for the missing schema descriptions.

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?

Description clearly states the tool fetches chemical components/ligands by short codes, with examples. The verb 'Fetch' and resource 'chemical components / ligands' make the purpose unambiguous and distinguish it from sibling tools like rcsb_get_entries or rcsb_get_polymer_entities.

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: use this to fetch chemical components by short codes. It also mentions rcsb_describe_data_object as an alternative for field discovery, offering guidance on when to use that tool. No explicit exclusions are given, but the scope is well-defined.

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