List leagues

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

With no annotations provided, the description does a good job disclosing behavior: it is a read-only listing operation returning all available leagues. The note about ordering (newest first for seasons) adds helpful context. No contradictions since no annotations exist.

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 two sentences and contains exactly what is needed: what data is returned, ordering, and usage guidance. No wasted words.

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?

Given no parameters, no output schema, and no annotations, the description covers the essential behavioral and functional aspects well. It could optionally mention that no authentication details are needed for this listing, but it is already complete enough for an agent.

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 schema has no parameters (0 params, 100% coverage by default), so the description does not need to compensate. It correctly implies no input is needed and focuses on explaining the output structure instead.

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 clearly states the tool lists over 90 leagues with specific fields (country, league key, seasons available). It distinguishes itself from sibling tools which are more specific to matches, teams, or tables.

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 says to call this tool first to resolve league keys and season strings, implying it is a prerequisite for other tools. It does not directly name alternatives but the purpose naturally differentiates it.

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