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

Annotations already establish readOnlyHint=true and openWorldHint=true, so safety is covered. The description still adds real behavioral context: that league-average values are returned alongside rows and that the position filter only affects the batter view. It omits pagination/rate-limit behavior, so not a 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?

Two tight sentences: the data returned and views come first, filters second, the position caveat and the routing hint close it out. Nothing is redundant or padded.

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, return values need no explanation, and annotations carry the safety profile. The description covers views, filters, the position caveat, and an alternative, which is nearly everything an agent needs; only pagination behavior is left implicit.

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 description coverage is 100%, so every one of the 10 parameters is already documented in the schema, including the note that position only applies to type=batter. The description's enumeration of filter categories restates rather than extends the schema, so the 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?

States a specific verb (Fetch) and a precise resource (Baseball Savant Expected Statistics rows plus league-average values) with the supported views named. It does not differentiate itself from the many other mlb_statcast_* siblings, only pointing at mlb_discovery for a different need, so it falls short of full sibling disambiguation.

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?

It gives clear context (batter/pitcher/team expected-stat views with the available filters) and routes one specific need, exact values, to mlb_discovery. There is no explicit when-not guidance or comparison to the other statcast endpoints, so it stops short of 5.

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