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

Annotations already cover read-only and open-world behavior, so the description's added context is useful: batch limit of 20, in-play sourcing, sport-specific detail preservation, and the fact that scheduled events return live false. It does not discuss error handling for invalid event ids, but the key behavioral traits are disclosed.

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 definition is front-loaded with the core action and scope, then adds useful caveats in a compact two-sentence form. The parenthetical sport examples are somewhat dense but still serve to clarify coverage.

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?

Given the existing output schema and annotations, the description supplies enough context for correct invocation: batch limit, in-play source, sport coverage, response structure note, and scheduled-event behavior. The only meaningful gap is the lack of explicit sibling differentiation.

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 schema has full description coverage and already explains that event_id accepts ids from any Sportsbook events listing, 1 to 20. The description reinforces the 'up to 20 events' limit but adds no additional semantics for the event_id parameter beyond what the schema provides.

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 names a specific verb and resource: 'Get live state for up to 20 FanDuel Sportsbook events from the in-play service.' It also clarifies sports coverage and the scheduled-event behavior. However, it does not explicitly distinguish this tool from the closely named sibling fanduel_sportsbook_live, leaving some ambiguity.

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 by 'Get live state... from the in-play service' and 'scheduled events return live false,' but the description never states when to use this tool instead of alternatives such as fanduel_sportsbook_live or event-specific siblings. The agent must infer the routing.

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