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

Annotations already declare readOnlyHint, idempotentHint and closed-world, so the safety profile is covered. The description adds a genuinely useful trait outside the annotations — 'Costs no API quota' — plus the domain note that Soccer (1) has the largest board. It does not describe return shape, but the id/name pairing is implied in sentence one.

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, front-loaded with the identity statement, then the trigger, then the operational caveat. Every sentence carries distinct information; nothing is repeated from the schema or annotations.

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 zero-parameter lookup with no output schema, the description supplies what is missing: what the return contains (sports and their numeric ids), when to reach for it, its quota cost, and a coverage caveat. An agent has everything needed to call 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?

The tool takes zero parameters, which is the baseline-4 case. There is no argument syntax to explain, and the description correctly spends its words on when to call rather than inventing parameter guidance.

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 ('List the sports pinnodds covers') plus the payload detail that matters ('with their numeric ids'). It also distinguishes itself from get_events by directing board-narrowing to that sibling's `query` parameter, so an agent can tell the two apart without opening either 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 an explicit trigger ('Call this first when the user names a sport and you need its id, or to confirm coverage') and names the alternative path for the adjacent task (use `query` in get_events to narrow). Both when-to-use and when-to-go-elsewhere are covered.

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