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

Annotations already declare readOnlyHint and openWorldHint, but the description adds substantive context: the return is limited to links and categories, no live market or account data is touched, and the underlying source page disclaims the information as unofficial. That disclaimer is behaviorally meaningful for an agent deciding whether to rely on the output, though pagination/format details are left to the output schema.

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 core action, followed by scope boundaries and a caveat. No sentence is filler; each adds either routing or reliability information.

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 listing tool with an output schema and annotation coverage, nothing essential is missing. Return shape is delegated to the output schema, and the description supplies the scope, exclusions, and reliability caveat an agent needs to call and interpret 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?

With zero parameters and 100% schema coverage, there is nothing for the description to disambiguate. Baseline for a no-parameter tool is 4, and the description correctly adds no redundant parameter prose.

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 public rulebook and settlement-source links on DraftKings Predictions) and explicitly scopes the output to source links and categories. It also distinguishes itself from market/quote/account/trade-slip tools, which differentiates it from siblings like draftkings_predictions_categories and draftkings_pick6_rules.

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 negative scoping ("it does not fetch markets, quotes, account state, or trade-slip data") tells an agent when this tool is the wrong choice and implicitly routes to market-oriented siblings. It stops short of naming a specific alternative or stating an explicit trigger condition, so it is clear context rather than full when/when-not guidance.

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