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

Annotations already declare readOnlyHint and openWorldHint, so the bar is lower; the description still adds genuinely behavioral detail — results arrive grouped into sport tabs, narrowed by competition pills, and page in fixed blocks of 20. It does not mention auth, rate limits, or whether the tab/pill titles are exact-match, but the iterative two-phase nature of the call is well 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?

Two dense sentences with the defining trait (grouped, tabbed search) front-loaded and the call sequence following. Every clause carries information, though the minimum-length rule is repeated from the schema and could have been dropped.

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?

With an output schema present, the description need not explain the return shape, and it correctly focuses on the navigation loop and character minimum. The state and timezone parameters are left entirely to the schema, which is acceptable at full coverage but leaves market scoping unaddressed in prose.

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 coverage is 100%, so the schema already documents q's 3–100 length bound, tab/pill sourcing, and start_index's step-of-20 semantics. The description largely restates those constraints; what it adds is only the ordering relationship (get tab and pill from a response before using them), which is close to what the schema's 'from a previous response' wording already conveys.

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 ('Search the FanDuel Sportsbook') and characterizes the variant precisely as a grouped, tab-and-pill search rather than a flat one. It never names the sibling fanduel_sportsbook_search, so the agent must infer which of the two search endpoints it wants from the tab/pill mechanic alone.

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 it to find events and competitions by name across sports' gives a clear use context, and the sentence spells out the operating sequence (q first, then tab/pill from the response, then next_start_index to page). No explicit exclusion or 'prefer X instead' statement against fanduel_sportsbook_search or fanduel_sportsbook_autocomplete.

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