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

Annotations already declare readOnlyHint and openWorldHint=false, so the safety profile is covered; the description adds real behavioral detail beyond that: newest-first ordering, delta semantics ('what finished matches changed', 'runs started or ended'), and the 'facts only' scope limit. idempotentHint=false is consistent with a time-delta feed.

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-loads the core behavior (changed finished matches, newest first) before the content enumeration. Dense but every clause carries information; the closing 'Facts only' is a useful scope fence rather than 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?

With no output schema, the description takes on describing returns and does so adequately by listing the fact categories and the localized sentence option. Combined with full schema coverage and clear annotations, an agent has what it needs to invoke it correctly.

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 all five parameters (lang, since, sport, league_id, min_importance) are already documented in the schema, and the description only restates the lang options. No additional syntax or interaction detail is provided, so 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+resource and enumerates the returned content (match story, runs, table places/zones, localized sentences). It reads as a 'what changed in this league' feed, which distinguishes it from get_standings and get_matches by scope. It stops short of naming a sibling to contrast with explicitly.

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 a concrete usage cue — "Use for 'what happened in this league today'" — which frames it as a recency/change feed rather than a lookup. No when-not or named alternatives, but the context is clear enough to route correctly against get_matches/get_standings.

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