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

Annotations only declare readOnlyHint and openWorldHint; the description adds substantive behavioral context beyond that, notably that team-sport players return a full structured profile while individual-sport players (e.g. tennis) return only profile and ranking text. This shape-varies-by-input warning is exactly the kind of thing an agent needs and annotations cannot convey.

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?

Three sentences, front-loaded with the primary return content, then the important edge case, then the id sourcing. No filler and every clause earns its place.

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-field enumeration is partly redundant, but the description's key added value is that the return shape depends on player type, which the output schema alone would not make obvious. It is complete enough for an agent to call the tool correctly given the 100% schema coverage.

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 100% and the schema already documents both id and slug origins. The description reinforces the id provenance ('from flashscore_search or a squad') and explains the returned data varies by player type, which is meaningfully more than the schema alone conveys, though it does not clarify the optional slug's matching requirement beyond what the schema states.

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 (returns) and resource (Flashscore player profile) and enumerates exactly what fields come back (country, birth date, team, position, age, market value, contract expiry, season stats). It also differentiates behavior by player category and names a sibling (flashscore_search) as the id source, so an agent can distinguish it from the many other flashscore_* tools.

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?

Tells the agent where to get the required id ('from flashscore_search or a squad'), which is real usage guidance, but gives no when-to-use vs when-not guidance relative to siblings like flashscore_team_squad or flashscore_player_transfers. Usage is implied rather than delimited.

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