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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and a closed-world domain, so the safety profile is fully covered by structured data. The description adds nothing beyond that: no mention of what a "player card" contains, what happens for an unknown id, or whether the lookup is basketball-specific.

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?

A single eight-word sentence with the lookup key front-loaded and no filler. It is efficient, though the brevity is partly under-specification rather than disciplined editing.

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 return values need not be described, and annotations cover safety, but the definition still leaves the one parameter undefined and the sport/domain ambiguous among many similarly named siblings. For a lookup tool in a crowded catalog, that is not sufficient to invoke correctly on the first try.

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 description coverage is 0% for the single required parameter, so the description carries the burden and only says "by id", without specifying whether this is an internal id, an external provider id, or an id returned by search_players. This is a case where the low coverage is not compensated for.

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 gives a verb and resource ("Get a player card") plus the lookup key ("by id"), which is more than a restatement of the name. However, "player card" is unqualified and does not say which sport or domain, while the sibling set contains get_football_player and search_players, so an agent cannot tell from the text alone which player universe this covers.

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?

"By id" implicitly signals a direct lookup rather than a search, which is a faint usage cue, but there is no explicit when-to-use, no statement of when to prefer search_players or filter_players instead, and no note that an id must first be obtained elsewhere. The guidance is left entirely to inference.

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