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

Annotations only declare readOnlyHint/openWorldHint; the description adds real behavior beyond that, namely newest-first ordering, the empty-list-means-none-recorded convention, and the not-found failure mode for individual sports. It stops short of 5 because field shape is carried by the output schema rather than the prose.

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?

Two sentences, zero filler, with the payload contents (date, type, fee text, both clubs) and the ordering front-loaded before the edge cases. 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 structure need not be spelled out, yet the description still names the key fields, the sort order, the empty-result semantics, and the failure mode for non-team sports. Nothing an agent needs to call this correctly is missing.

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 100%, so the id (eight-character Flashscore id from a player URL) and the optional slug are already fully documented in the schema. The description adds no parameter-level guidance, so the baseline 3 applies.

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 a team-sport player's Flashscore club history') and immediately scopes the domain to team sports, which separates it from flashscore_player_injuries and from the team-level flashscore_team_transfers. An agent can tell what it retrieves and for whom without opening the 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?

Provides an explicit when-not condition: individual-sport players have no transfers page and return not found, so the agent knows this tool is inapplicable to tennis/golf style players. It does not name any alternative sibling (e.g., flashscore_player or flashscore_team_transfers) for those cases, which keeps it just short of a 5.

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