List configured MFL leagues

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

Annotations already declare readOnly/idempotent/non-destructive/closed-world, so the safety profile is covered. The description adds genuinely useful context beyond them: the precise returned fields and the security guarantee that API keys are never returned. It stops short of describing ordering or error behavior, so a 4 rather than 5.

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?

Front-loaded with purpose, then the when-to-use triggers, then args — a sound order with no wasted prose. The Args block duplicates the schema's own description nearly verbatim, which is minor redundancy rather than a structural flaw.

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?

With no output schema present, the description compensates by enumerating the returned fields and their meaning, and it covers triggers, safety, and defaults. An agent has everything needed to call and interpret this tool.

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?

Schema coverage is 100% and the single parameter is fully documented with default and enum, so the schema carries this dimension. The description's Args section merely repeats response_format without adding format-specific syntax or guidance, so baseline 3 applies.

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?

Specific verb (list) + resource (MFL leagues/seasons) plus the exact fields returned (alias, league ID, franchise ID, seasons with API key, default league). This clearly separates it from siblings like mfl_get_league or mfl_get_standings, which fetch league content rather than server configuration.

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?

Explicitly states when to call it: first when the user names a league by nickname, references 'last season', or when another tool reports an unknown league or missing API key. This is a concrete when-to-use rule coupled to observable triggers, not vague advice.

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