fpl_h2h_league

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

Beyond the readOnlyHint/idempotentHint annotations, the description discloses key behaviors: the return structure, the distinction between total (H2H points) and points_for (FPL points), the ranking on total, the auth behavior (works without key, FPL_SESSION_COOKIE unlocks more), and the 404 on classic-league ids in the schema. This is rich, useful context.

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?

The description is well-organized and front-loaded with the core purpose. It uses a code block for the return shape and a separate example and auth note. However, it is slightly lengthy and the example ('An H2H table' followed by an input object) is a bit confusing, so it loses a point.

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 no output schema, the description fully explains the return payload, field meanings, ranking logic, and auth prerequisites. It also covers edge cases (404 for classic ids) and provides an example. This is a complete and self-contained description for the tool's complexity.

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?

The input schema already provides full coverage (100%) for both parameters, including that leagueId is an H2H league id from fpl_manager and that a classic-league id 404s. The description adds only a trivial example, so it does not meaningfully enhance parameter understanding beyond the schema.

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 begins with 'Head-to-head league standings with win/draw/loss records,' clearly identifying the tool's function and resource. It differentiates from siblings like fpl_classic_league by explicitly focusing on H2H scoring and even notes in the schema that a classic-league id 404s, reinforcing the distinction.

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 description provides clear context that this is for H2H league standings, and the schema adds that classic-league ids are invalid. However, it does not explicitly name alternatives like fpl_classic_league or state when to prefer one over the other, so the guidance is implied rather than explicit.

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