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

The annotations already declare a safe read (readOnly, idempotent, non-destructive, closed-world), and the description adds real behavioural context on top: only Spain and Russia have public licence lookup, a licence alone does not bring rounds, and the insistence branch is conditional on insist_on_rfeg. The only soft spot is that it describes outcomes via route tokens rather than the actual response shape, and references a flag (insist_on_rfeg) that is not in the schema, which could briefly confuse an agent.

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?

Purpose is front-loaded and every clause carries information — the route enumeration, the RFEG warning, the check_licence caveat, and the sibling pointer all do distinct work. It is a dense single paragraph with heavy inline parentheses, so scanning takes effort, but there is no filler to cut.

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?

With no output schema, the description carries the burden of explaining returns and mostly discharges it by listing the possible route values and what each implies. Combined with the licence-lookup country restriction, an agent has enough to call the tool and interpret the answer; only the literal response envelope is unstated.

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 coverage is already 100% for the single boolean, so the baseline would be 3; the description earns the bump by adding meaning to check_licence=true — it queries the licence on file in the player's own federation, and only Spain and Russia support that. It also makes clear the parameter does not extend to other players.

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+resource ('su federación y por dónde le llega el golf oficial') and goes further by enumerating the exact route values it can return (rfeg_synced, connect_rfeg_account, federation_lookup, wagr, scorecards). It explicitly separates itself from the sibling that searches other players ('para buscar a otro jugador está search_federated_player'), so an agent can route correctly without opening any schema.

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 precondition for calling it ('Úsala antes de mandar a nadie a la RFEG: un jugador internacional no tiene por qué estar federado en España') and names the correct alternative tool for the adjacent task (search_federated_player). It also scopes the conditional behaviour of check_licence and even gates how insistent the agent should be about connecting an account.

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