get_credible_set_by_id

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

The description is consistent with the readOnlyHint annotation, which already indicates a safe read operation. However, no additional behavioral details are disclosed (e.g., response shape, error conditions, or pagination). The presence of an output schema somewhat mitigates the need for return details.

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 a single, concise sentence that front-loads the action and resource. There is no repetition, empty filler, or unnecessary detail—appropriate for a 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?

Given the low complexity (one parameter, output schema present, readOnlyHint), the description is minimally viable but lacks usage guidelines and deeper parameter semantics. It is sufficient for a straightforward fetch, but not as rich as it could be for disambiguation.

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 has zero description coverage for study_locus_id, and the description only says 'specific study locus credible set,' which adds minimal meaning beyond the parameter name itself. It does not explain the ID format, what constitutes a 'study locus credible set,' or any constraints.

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 ('Fetch') and the specific resource ('detailed information for a specific study locus credible set'). It distinguishes from siblings like get_credible_sets or get_credible_set_colocalisation by implying a single, ID-based lookup, though it does not explicitly mention the ID parameter or contrast with list endpoints.

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?

No guidance is provided on when to use this tool versus alternatives. The description does not state prerequisites (e.g., needing a study_locus_id) or mention other related credible-set endpoints, leaving the agent to infer usage from the tool name and schema.

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