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

Annotations already declare readOnly, idempotent, non-destructive, so safety is covered. The description adds genuinely useful behavioral context beyond that: the result is probabilistic, derived from 5,000 simulations of the rest of the season, which tells the agent to expect modeled probabilities rather than deterministic facts. It says nothing about caching or performance, keeping it below a 5.

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?

A single tight sentence: the usage condition is front-loaded and the output content is appended in a compact clause. No filler or redundant restatement of the name.

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 usefully previews the return shape (win and top-3 probability per manager) and the simulation basis. For a two-optional-param, read-only tool this is nearly complete; only the empty-parameter fallback behavior lives solely in the schema.

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% with only two optional params, so the schema already documents that team_id and league_id accept IDs or FPL links and may be left empty. The description adds no parameter-level detail, so the 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?

The description states a specific verb and resource — computing each manager's win and top-3 probability in their mini-league — plus the mechanism (5,000 season simulations). It implicitly separates itself from the get_mini_league sibling by framing the output as odds rather than standings, though it never names the sibling 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?

It gives a clear trigger: use when an FPL manager asks their chances/odds of winning their mini-league. No when-not condition or explicit alternative is named, so it stops short of full routing guidance.

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