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

Beyond the readOnlyHint/openWorldHint annotations, the description discloses caching (five minutes per process), that the catalog tracks a rotating published asset via its own manifest so contents can change, the negative-EA-ID edge case for concept rarities, and that no authentication is required. These are exactly the non-obvious operational traits an agent needs and none of them are derivable from the annotations.

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 key points are front-loaded: what it returns, then identifier semantics, then caching and edition caveats. It is dense but nearly every clause carries real information; the closing "Takes no input" is slightly redundant with an empty schema and the phrase about no unqualified filter being exposed is somewhat compressed.

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?

Return values are covered by the output schema, so the description is free to spend its words on the things the schema cannot express: identifier conventions, caching, rotating source data, and edition scoping. For a zero-parameter read tool this leaves no meaningful gap.

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?

With zero parameters the schema baseline is 4, and the description reinforces it with "Takes no input." It also clarifies the semantic meaning of the identifier values found in the results (internal id vs eaId), which adds useful meaning even though there are no inputs to describe.

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?

"Get the published FC27 card catalog and return its native groups: clubs, nations, leagues, rarities and the source role metadata" states a specific verb and resource and enumerates the returned groupings. The line about player filters taking the EA id makes clear this is the lookup catalog, not the player list, so an agent can separate it from futgg_fc27_players without opening a 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?

It gives actionable context for when this tool is the right one: it is the source of eaId values that player filters consume, and it is explicitly scoped to FC27 with no account or purchase filters. It stops short of naming an alternative for cases where the agent wants definitions or other static reference data, so routing guidance is clear but not exhaustive.

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