list_leagues

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

With no annotations, the description carries the burden of disclosing behavior. It implies a read-only listing operation and reveals that active status is included, but it does not explicitly mention the absence of side effects or any other behavioral traits. For a simple list tool, this is adequate but not highly transparent.

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 a single, concise sentence that conveys both the content (all leagues) and a key detail (which is active). Every word earns its place, with no redundancy or fluff.

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 tool's simplicity (0 parameters, no nested objects, output schema present), the description fully covers what the tool does. It specifies what is returned and the inclusion of active status, which is sufficient for an agent to understand the tool's purpose.

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, and the schema covers 100% of them (none exist). Per the baseline rule for 0 params, a score of 4 is appropriate, and the description does not need to elaborate on parameter meanings.

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 that the tool outputs every league the user has set up and indicates which one is active. Although it lacks an explicit verb like 'list' or 'show', the meaning is unambiguous and distinguishes it from sibling tools such as switch_league or configure_league.

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?

Usage is implied: the name and description suggest using this tool when needing an overview of leagues and the active one. There is no explicit comparison to alternatives, but for a simple listing operation, the context is sufficient.

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