mfl_my_leagues

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

Annotations declare readOnlyHint, openWorldHint, and idempotentHint, so the read-only nature is covered. The description adds the cookie dependency, the return format, and the note that it works without a key but MFL_COOKIE unlocks more, which goes beyond the annotations. This is valuable context, though the 'more' is vague.

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 concise and well-structured: it leads with the purpose, then return format, then auth. Each sentence is informative, and the example is nestled in. No 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?

The description is complete for a read-only tool: it explains the key output (franchise_id), the required parameter (year), and the authentication requirement. Even without an output schema, the return structure is provided. Nothing needed for correct usage is missing.

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?

Input schema has 100% coverage: JSON and TYPE are described as 'Leave as-is,' year is required, and FRANCHISE_NAMES is explained. The description does not add meaning beyond the schema, but it does provide an example with 'year'. Baseline 3 is appropriate since the schema carries the burden.

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 purpose: 'Every league YOU are in, with your franchise id in each.' It also clarifies its role as 'The way to find the ids every other tool wants,' distinguishing it from sibling tools. This is a specific verb+resource with clear scope.

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 explains when to use this tool: to obtain league and franchise IDs needed by other tools. It also warns that 'Returns nothing useful without MFL_COOKIE' and gives an example call, providing strong usage context.

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