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

Annotations cover the safety profile (readOnly, idempotent, non-destructive, openWorld), so the description's real contribution is the return shape: the reference specialty plus all substitutable members with their fields. With no output schema, that disclosure is genuinely useful. It does not cover error/empty-group behavior, keeping it short of a 5.

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?

Two sentences, no filler, with the what-it-returns content front-loaded ahead of the usage instruction. Slightly dense in the enumeration but every clause carries information.

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 single-id lookup with no output schema, the description covers purpose, provenance of the id, and the returned structure, which is enough to invoke it correctly. Only minor gaps remain (empty/not-found behavior, ordering of members).

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?

Only one parameter and schema description coverage is 100%, so the schema already documents group_id. The description adds provenance (the id originates from fr_medicine's generic_group.group_id), which largely duplicates the schema text, so the baseline 3 applies.

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?

States a specific verb and resource: retrieve one BDPM generic group by id, and enumerates the payload (reference princeps specialty plus every generic/substitutable member with CIS code, denomination, generic type). This is clearly distinct from the search/browse siblings fr_medicine and fr_medicine_search.

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?

Gives an explicit trigger: use after fr_medicine returns a generic_group.group_id, and states the goal (see every interchangeable specialty in the group). No when-not guidance is offered, but the tool is narrow enough that the chaining condition is the only decision point.

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