rcsb_get_branched_entities

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

Annotations already cover the safe read-only nature (readOnlyHint, idempotentHint, non-destructive). The description adds useful behavioral details: unknown IDs are returned under 'not_found', the default field set is enumerated, and users are directed to rcsb_describe_data_object for custom field discovery. This goes beyond the annotations without contradicting them.

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 well-structured with a brief opening followed by separate Args entries. It is slightly lengthy due to the GraphQL example, but every sentence contributes necessary information with no filler. The format is scannable and front-loaded.

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 provides default fields, error handling for unknown IDs, and a path discovery mechanism. Since an output schema is present (per context), detailed return structure is not required. It is complete enough for safe selection and invocation, though it does not mention pagination or rate limits.

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?

Both parameters are thoroughly explained. entity_ids is described with a concrete example and behavior for unknown IDs; fields is explained with GraphQL selection syntax and a pointer to discover valid paths. This fully compensates for the schema's 0% description coverage and adds significant semantic meaning.

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 opens with 'Fetch branched (carbohydrate / oligosaccharide) entities' which clearly specifies the verb, resource, and scope. The example and the sibling context distinguish it from polymer/nonpolymer or instance-level getters, making its purpose unambiguous.

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 gives no explicit guidance on when to use this tool versus siblings like rcsb_get_branched_entity_instances or rcsb_get_polymer_entities. It focuses on mechanics (fields, defaults) but does not state selection criteria or exclude alternatives, leaving usage context to be inferred from the tool name.

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