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

Annotations only cover readOnly/openWorld, and the description adds substantial context beyond them: the full status vocabulary (finished, scheduled, cancelled, annulled, abandoned, no_show, other), result_qualifier such as after_penalties, the cups/rounds fallback where a round id works as competition_id, and the glyph-font decoding caveat. That is real behavioral disclosure, not restatement.

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?

Front-loaded with the core capability and tightly packed; the alternative-tool routing is correctly placed at the end. The middle section is a long chain of clauses in one sentence, slightly harder to parse than necessary, but no sentence is filler.

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 3-parameter read tool with an output schema and only safety annotations, the description covers addressing modes, edge cases (cups/rounds), result semantics and data-decoding caveats. Nothing an agent needs to call 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 the baseline is 3; the description still adds value by clarifying that matchday ranges to the competition's matchday_count (reported in the response) and that cups have no numbered matchdays. It stops short of adding anything beyond the schema's mutual-exclusion note for date vs matchday.

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?

Opens with a specific verb+resource ("Returns the matches of a competition's current matchday") and enumerates the three addressing modes (current, numbered, date), then names the sibling tools it is not. An agent can distinguish it from fussballde_match_plan and fussballde_match without opening any 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?

Explicitly routes away: "Use fussballde_match_plan for the whole season schedule or fussballde_match for one match in detail." It also states the domain constraint that cups/tournaments have no numbered matchdays, which is exactly the case an agent would otherwise get wrong.

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