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

Annotations already declare readOnlyHint and openWorldHint, so safety is covered. The description adds a genuine failure mode beyond the structured fields: an unserved country code returns not found, which tells the agent to validate input and expect a 404-style outcome. It omits pagination/result-size behavior, keeping it below 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 short sentences, each earning its place: scope first, then the required parameter constraint, then the motivating use case. Front-loaded and free of redundancy.

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 an output schema present, the description correctly avoids explaining return values while still noting the summary-plus-sport-key shape. For a single-parameter read tool with annotations covering safety, 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 country parameter's type, format (ISO 3166-1 alpha-2), examples, and not-found behavior are already fully documented in the schema. The description merely restates that, adding no new syntax or semantics — the baseline 3 for a schema-documented single parameter.

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 the events trending in one country across every sport' — and clarifies the unit of return ('event summary with its sport key'). This cleanly separates it from sibling tools like sofascore_trending_players or sofascore_live_events without opening a 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?

Gives a clear use case: 'Use it to see what fans in a market are following right now,' which orients the agent to the trending/discovery intent. It stops short of naming alternatives or stating when not to use it (e.g., vs sofascore_trending_players or sofascore_scheduled_events), so it is clear context but not full routing guidance.

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