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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safe-read profile is covered. The description adds little behavior beyond routing ('use mlb_discovery for exact values') and does not describe pagination, return format, or rate constraints. With annotations carrying safety, a 3 is appropriate.

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 sentences with zero filler. The core purpose is front-loaded ahead of the routing guidance, and each clause carries distinct information.

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, annotations covering the safety profile, and full param coverage in the schema, the description supplies what is missing: what the tool returns conceptually and which siblings to use instead. Minor gap is the lack of an explicit condition separating it from the individual arsenal views.

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 all nine parameters are already documented in the schema (including the note about avg_spin pre-2015 and first-party browser-side team filtering). The description adds no parameter-level detail, so baseline 3 is correct.

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) plus a precise resource (Baseball Savant Pitch Arsenal leaderboards) and enumerates the metrics covered (pitch speed, usage percentage, spin by pitch class). It also distinguishes itself from sibling tools by naming the related individual arsenal views, so an agent can route correctly without opening a schema.

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 names alternatives (mlb_statcast_pitch_arsenal, mlb_statcast_pitch_arsenal_details, mlb_discovery) and gives the reason for reaching for mlb_discovery (exact values). However, it does not clearly state the condition that selects this leaderboard view over the individual arsenal views, leaving that distinction to inference.

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