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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered. The description adds real behavioral context beyond that: the default date window is the current season, kind controls whether paging and competition filters apply, and each match names its competition and team type. No mention of rate limits or result caps, which keeps it from a 5.

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 what it returns and followed immediately by the mode semantics and the alternative routing. The middle sentence is long and clause-stacked, but nearly every clause carries distinct information.

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?

For a 7-parameter read tool with an output schema and read-only annotations, everything an agent needs to call it correctly is present: defaults, mode semantics, paging behavior, and sibling routing. Return-value detail is legitimately delegated to the output schema.

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 the baseline is 3, but the description adds conceptual meaning the schema only implies field-by-field: that kind is a mode switch governing whether the date window and limit/offset are meaningful. That interplay is the non-obvious part of this parameter set.

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 with scope: fixtures and results across all of a club's teams, including senior and youth. It explicitly contrasts itself with fussballde_club and fussballde_team_matches, so an agent can pick it out of the sibling set 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?

Names the alternatives and the condition that selects each: fussballde_club for the club profile, fussballde_team_matches for one team. It also explains which mode (all/next/previous) fits which question, so the routing decision is fully specified.

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