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 only that results are game-level play records tied to a leaderboard row; it says nothing about pagination, result volume, or how entity_id must be sourced, which for a 10-param detail endpoint is a modest gap.

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?

A single front-loaded sentence with no filler, stating the action, the resource, and the leaderboard context up front. It is dense with domain jargon ('Run, Fld, or Pit', 'Arm Value') but wastes no words.

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?

An output schema exists, so return values need no explanation, and the schema fully documents all parameters. The description supplies the crucial drill-down context, though it omits how to obtain the required entity_id and any note on the leaderboard it depends on.

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 10 parameters are already documented (type values Run/Fld/Pit, split, team_id, year range, game_type, key_base_out, minimum_opps, with_team_only). The description restates the type/entity concept but adds no syntax or defaults beyond 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 resource ('game-level play records') and scopes it to rows expanded from the Baseball Savant Arm Value leaderboard, which implicitly separates it from the mlb_statcast_arm_value leaderboard sibling. It does not name the parent tool explicitly, so an agent must infer the drill-down relationship.

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?

Usage is only implied: the phrase 'expanded from the ... leaderboard' suggests this is a second-step call after retrieving a leaderboard row, but the description never states prerequisites, when to prefer this over the sibling leaderboard tool, or when it is not appropriate.

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