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

Annotations declare readOnly and openWorld, so safety is covered; the description adds real behavioral context: teams default to the current season unless season is set, and competition_kind filters which team types appear. It also tells the agent where club ids come from (club_id on teams and matches). It does not discuss result size or whether large clubs paginate.

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?

Front-loaded with the return payload, followed by the two optional filters and then sibling routing. Every sentence carries information – no restatement of the tool name, no filler.

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?

An output schema exists, so the description needn't explain the response shape, and it focuses instead on scope, defaults, and routing. Combined with annotations and full schema coverage, an agent has everything needed to call this correctly.

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%, so the baseline is 3, but the description adds genuine meaning: season is framed as 'set season for an earlier one' (default = current), and competition_kind is characterized as keeping only championships, cups, friendlies, etc. The four-digit season format itself is left to the schema.

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 ('Returns one club') and enumerates exactly what is returned: name, federation, team counts, profile facts, and teams with competitions and team types. This clearly separates it from fussballde_club_search (which would locate a club) and fussballde_club_matches.

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?

Names two alternatives explicitly – fussballde_team for a single team and fussballde_club_matches for fixtures – and explains when to use season and competition_kind to narrow results. It stops short of saying when not to use this tool (e.g. when you don't yet have a club_id and should use club_search), but the routing context is solid.

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