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

Annotations already cover safety (readOnlyHint=true) and open-world behavior, so the description's added value is the shape of the response: teams grouped by conference/division with betting records and next game. It adds meaningful content context beyond annotations, though it says nothing about response size, pagination, or league availability limits.

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 what is returned, then the practical routing advice. Slight redundancy in repeating the league enum from the schema is the only waste.

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 needn't enumerate fields, and it correctly highlights the two downstream-useful outputs (team slug, sections). 'Sections to see which pages the league has' stays a bit vague, but nothing critical for calling the tool is missing.

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?

Only one parameter with 100% schema description coverage, and the description merely re-lists the same league values (nfl, nba, mlb, college-football, college-basketball) already in the schema, adding no format or default nuances. Baseline 3 applies since the schema does the work.

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 a FanDuel Sportsbook league's teams') plus the grouping dimension (conference/division) and the payload (ATS, money line, over/under records, next game). An agent can distinguish this from team-specific siblings like fanduel_sportsbook_team_odds without opening a schema.

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?

Explicitly tells the agent when to reach for it: to obtain the team slug that other team tools require, and to discover which pages a league has via sections. It doesn't name an alternative tool or state exclusions, but the intended call sequence is clear.

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