list_leagues

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

With no annotations provided, the description carries the burden of behavioral disclosure. It states the scope ('All competitions PlayerElo covers'), the fields returned (id, name, country), and its relationship to get_league_ranking. It does not mention pagination or auth, but for a simple zero-parameter list tool these are likely unnecessary.

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: the first states the tool's output and scope, the second gives a cross-reference to get_league_ranking. Every word earns its place; there is no redundancy or filler.

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 the output schema exists and the tool has zero parameters, the description sufficiently covers the purpose, output fields, and usage context. It also connects to a dependent tool, making it complete for this simple list operation.

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 there is nothing to explain. The mention of 'league_id' is for the sibling tool, not this one. Baseline 4 applies for no parameters.

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 identifies the tool's purpose: it lists all competitions covered by PlayerElo, with each league's id, name, and country. This is a specific verb+resource statement that distinguishes it from sibling tools like get_league_ranking, which consumes the league_id.

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 an explicit usage instruction: 'Use a league_id with get_league_ranking.' This tells the agent how to use the output and positions this tool as a prerequisite. It doesn't explicitly say when to use this tool vs alternatives, but no alternatives exist for listing leagues.

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