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

Annotations already declare readOnly, idempotent, non-destructive behavior, so safety needs no restating. The description contributes that the result covers all 20 clubs and includes confidence scores plus predicted formations, which is useful payload context, but says nothing about refresh timing or what is returned when predictions are unavailable.

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 front-loaded sentence with no filler, hedging, or repetition. Scope (all 20, current gameweek) and payload (formations, XIs, confidence) are both packed in without 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?

For a no-parameter, read-only tool with no output schema, the description covers the essentials: what comes back and for which gameweek. The remaining gap is behavioral edge cases (stale or missing predictions), which is minor at this complexity level.

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 takes zero parameters, so the baseline is 4. There is nothing for the description to disambiguate about inputs, and it correctly avoids inventing any.

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?

"Retrieve the complete slate of all 20 Premier League predicted formations, starting XIs, and confidence scores" names a specific verb, resource, and payload. The "all 20" scope implicitly separates it from the singular sibling get_predicted_lineup, but it never names that sibling, so the differentiation is inferred rather than stated.

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 phrase "for the current 2026/27 Gameweek" gives an implicit trigger condition (use when you need the whole slate for the live gameweek). However, it offers no explicit when-not guidance and does not tell the agent to prefer get_predicted_lineup when only one team is of interest.

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