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

Since readOnlyHint and openWorldHint are already declared, the description's added value is the registration caveat that silently empty results can occur, plus a concrete account of what a response contains for team/competition discovery. It stops short of describing volume, ordering, or whether all season matches are returned in one response.

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 tight sentences, front-loaded with what is returned, then the data-availability caveat, then the alternative-tool routing. The enumerated per-match field list is somewhat redundant against the output schema but is compact and aids call-fitness judgement.

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 explanation is optional; the description nonetheless covers the registration limitation, the multi-team selection workflow, and the sibling alternative. Nothing an agent needs to invoke it 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 coverage is 100%, so season, team_id and player_id are already fully documented with defaults and provenance. The description reinforces the team_id chaining idea ('so another team can be selected with team_id') and implies season scoping, but adds no format or edge-case detail beyond the schema, 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 registered player's matches') scoped to one season and team, and enumerates the per-match content (date, teams, result, goals, substitution minute, minutes played). It explicitly distinguishes itself from the sibling fussballde_player, which covers the profile and season totals.

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?

Gives an explicit routing rule: 'Use fussballde_player for the profile and season totals.' It also states the precondition ('Basic profiles without registration have no match data') and explains the two-step pattern of reading the teams list before passing team_id, so an agent knows both when to call this and when not to.

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