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

Annotations already cover read-only, idempotent, and openWorld behavior, so the bar is lower. The description adds genuinely useful non-obvious context: coverage is per-competition and uncovered matches return found:false with a reason rather than an error, which tells the agent how to interpret a miss.

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, each earning its place: scope+fields, usage trigger, and coverage caveat. Front-loaded with the core purpose and no 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 single-event read tool with 100% schema coverage and annotations carrying the safety profile, this covers what an agent needs: what it returns, when to use it, and the failure/coverage behavior. No output schema exists, so return-shape detail isn't required.

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 both parameters (event_id and _apiKey) are already documented in the schema, including the free-tier vs supporter-key rate-limit note. The description adds no parameter-level detail beyond that, so the baseline of 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 (team-by-team match statistics for one event) and enumerates concrete fields (shots on goal, corners, possession, fouls, passes) as home/away pairs. This clearly distinguishes it from siblings like event_detail, event_lineup, and event_timeline without needing their schemas.

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 names the use case: 'Use for settling shot-count, corner and possession questions.' This gives clear context for selection, though it does not explicitly exclude or contrast with any specific sibling tool.

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