fpl_players

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

Annotations already indicate readOnlyHint, openWorldHint, and idempotentHint, and the description adds substantial context beyond those: the large response size warning, the fact that the data is trimmed from 105 to 22 fields, the upstream blob size (362k tokens), the meaning of status codes, and the unit convention for now_cost. This gives the agent a clear behavioral model of what to expect.

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 dense but well-structured, with a clear statement of purpose, a prominent size warning, a detailed return shape, unit/status explanations, and an auth note. The 'Example: Every player, key fields' line is slightly redundant filler, but the rest of the content is information-dense and front-loaded.

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?

There is no output schema, so the description carries the full burden of documenting return values. It does this thoroughly by listing all 22 fields, explaining the now_cost unit, defining status codes, and warning about the large token count. This is complete enough for a zero-parameter bulk read tool.

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 tool has zero parameters, so the schema is empty and coverage is 100%. The description doesn't need to explain parameter meaning, and the baseline of 4 for zero-parameter tools applies. The description does not introduce any parameter-related ambiguity.

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 opens with 'Every FPL player with price, form, ownership, expected goals and availability,' using a specific verb ('Every FPL player' as the resource) and a precise field list. It also explicitly distinguishes itself from fpl_player_detail by directing users to that tool for one player's depth, which clearly separates its scope from a close sibling.

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 explicitly states when to use this tool (for all players with key fields) and when not to (for one player's depth, use fpl_player_detail). It also provides a practical usage guideline by warning about the large token size (~65k tokens) and mentions authentication prerequisites (works without key, cookie unlocks more).

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