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

Annotations already cover the read-only, open-world safety profile, so the description's real contribution is the behavioral constraint that only NFL and NBA have a stats page and that the returned shape differs by league (scoring/offense/defense/special teams vs totals and averages). That is context an agent cannot get from annotations, though nothing is said about per-season vs current-season scope.

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 sentences, front-loaded with the resource and what it returns, followed by the league scope restriction. Nothing extraneous.

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 and fully described parameters, the description only needs to set scope, which it does by naming the supported leagues and the differing stat categories. A brief note that the team slug must come from fanduel_sportsbook_teams and that league must match the team would close the remaining gap.

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%: both league and team are fully documented, including the league list and that stats exist only for nfl/nba. The description's league restriction largely repeats the schema hint, adding no new parameter syntax or format detail, so baseline 3 applies.

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 ('Get a FanDuel Sportsbook team's season statistics') and enumerates the stat categories returned per league. It implicitly distinguishes itself from league-wide stats and player stats siblings, but never names them, so an agent must infer the boundary.

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 'NFL and NBA only' constraint is useful scoping, but there is no explicit guidance on when to prefer this over fanduel_sportsbook_stats, fanduel_sportsbook_event_stats or fanduel_sportsbook_player_stats. The team-slug dependency is only conveyed through the schema, not the description.

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