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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds real behavioral value beyond that: the LIVE/UPCOMING filter and exclusion of completed-only sports, plus the underlying endpoint GET /sports. It does not mention auth or rate limits, but a public read endpoint with zero parameters needs little more.

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?

Two compact sentences with the most important constraint front-loaded in the first clause. The endpoint is a single cheap addendum; nothing is wasted.

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, read-only list tool with annotations covering safety and no output schema to warrant return-value prose, the description says what is needed. The only mild gap is that the shape of returned sport objects is unspecified, though the title and endpoint make the type evident.

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 no parameters, so there is nothing for the description to disambiguate. Baseline of 4 applies; the endpoint hint adds marginal value for agents reasoning about backend behavior.

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 (List) and resource (sports) with an explicit scope qualifier: only sports with LIVE or UPCOMING programs. It does not name or contrast a sibling tool, but the scope is precise enough that an agent can tell what set is returned.

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?

The parenthetical clarifies an exclusion (sports with only completed programs are not listed), which implicitly tells the agent when this tool will not return a sport. However, it never names an alternative tool for completed/historical sports or states prerequisites, so usage is only implied.

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