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

No annotations are provided, so the description carries the burden of behavioral disclosure. It states that no API key is required and clearly indicates this is a read-only listing operation ('List... returns...'). It also reveals what the response contains: sport keys, live event counts, and book counts. It does not discuss rate limits or error behavior, but these are not critical for a simple zero-parameter list.

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?

The description is three short sentences with no filler. The primary action is front-loaded in the first sentence, the authentication requirement is a single clear note, and the return contents and purpose are compactly covered.

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 tool with an output schema and no annotations, the description is complete: it states scope, auth requirements, response contents, and intended use. The only minor ambiguity is the exact meaning of 'retail /live surface,' but the rest of the description compensates by explaining what the agent can discover.

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?

There are no parameters in the input schema, so the baseline is 4. The description cannot add parameter-level meaning, but it usefully describes what the invocation will return, which is the only relevant semantic information for a parameterless call.

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?

The description opens with a specific verb and resource: 'List currently active live sports on the retail /live surface.' It clearly distinguishes this from siblings like parlayapi_list_sports by emphasizing 'currently active' and by stating it returns live event and book counts, not just sport names.

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?

Usage is implied through the phrase 'so agents can discover what is active right now,' which tells the agent when this tool is useful. However, it does not explicitly mention when not to use it or name alternatives among the many sibling tools, such as parlayapi_list_sports or parlayapi_live_search.

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