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

With no annotations, the description must carry the burden, and 'List' reasonably communicates a read-only operation with no side effects. However, it does not disclose the effect of the active_only parameter or the default filtering behavior, and it gives no indication of output shape beyond sport keys.

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 short, front-loaded with the primary action, and then immediately gives the practical usage context and concrete examples. Every sentence earns its place and there is no redundant 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?

This is a low-complexity list tool with one optional parameter and an output schema, so the description does not need to detail return values. It gives enough context for an agent to use the tool in a workflow, though mentioning the active_only default would make it fully complete.

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 description coverage is 0%, so the description should compensate for the single active_only parameter, but it never mentions it. The phrase 'available sport keys' only weakly implies active-filtering behavior, leaving the agent to infer parameter semantics from the schema alone.

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 clearly identifies a specific verb ('List'), a resource ('available sport keys'), and their purpose in subsequent calls, with concrete examples like baseball_mlb. It does not explicitly differentiate itself from sibling list-like tools such as parlayapi_live_sports, so it stops just short of a 5.

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?

'Use these in subsequent calls' gives clear workflow context and signals that this tool is a prerequisite for callers needing sport keys. It does not state exclusions or compare against alternatives, but the intended usage is unambiguous.

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