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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered and this is clearly a safe external read. The description adds that the response is organized into schedule and futures tabs with markets and odds, but says nothing about state/market dependence, rate limits, or what happens when a competition is not offered in the requested market.

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 tight sentences with the resource and payload front-loaded and the dependency requirement second. The parenthetical '(tabs schedule and futures)' is slightly awkward but does add real information about page structure; nothing is wasted.

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?

An output schema exists, so return values need no prose, and annotations cover the safety profile. The description supplies the critical missing piece — the ID sourcing chain — and the tab structure. It could have added a note that the tool is market/state dependent, but overall an agent can call it correctly from this.

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 100%, so every parameter is already documented, including the tab slug, state enum list, market_type values, and the integer event_type_id mapping. The description only restates the two required IDs and where to source them, which largely duplicates the competition_id schema text — baseline 3.

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 ('Fetch'), a specific resource ('one FanDuel Sportsbook competition'), and enumerates the content returned (schedule and futures tabs, markets and odds). The singular 'one competition' implicitly scopes it apart from league/sport siblings, though it never names them explicitly.

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?

Gives an actionable prerequisite chain: event_type_id and competition_id must come from a league or sport response's competitions, which tells the agent to call fanduel_sportsbook_league or fanduel_sportsbook_sport first. No explicit when-not or exclusion guidance, so it stops short of a 5.

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