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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety is covered; the description adds useful context that this is a reference/enumeration surface spanning three upstream APIs and that values are 'current' (i.e., live-changing). It does not discuss caching, stability, or staleness of the returned selector values.

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?

Two tight sentences with zero filler: the first defines what is fetched and where, the second front-loads the usage trigger. Nothing is redundant or restated.

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 an output schema present, the description need not enumerate return values, and zero parameters keep the contract simple. The mention of game/roster/stat/leaderboard/Statcast value families rounds out scope; only a pointer to how those values feed specific sibling calls 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?

The tool takes zero parameters, so the baseline is 4 and there is nothing in the schema requiring descriptive compensation. The description correctly avoids inventing parameter guidance for a parameterless tool.

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?

States a specific verb and resource -- fetching MLB.com's menu sections and supported selector values -- and scopes it to three named surfaces (Stats API, Pipeline, Baseball Savant). This distinguishes it from the many mlb_* data siblings (mlb_game, mlb_player, mlb_statcast_*) as the enumeration/discovery tool, though the phrase 'menu sections' is slightly jargon-y.

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?

'Use this before a filtered MLB query when you need valid game, roster, stat, leaderboard, or Statcast values' gives an explicit precondition and use context. It does not explicitly name which sibling tools it feeds or state when not to call it, so it stops short of the top band.

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