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

Annotations already declare readOnlyHint/idempotentHint/destructiveHint, so the safety profile is covered. The description still adds substantive behavior beyond that: the 0-100 scoring scale, the fact that higher favors the hitter, the three sub-metrics (combined/pitch_mix/zone_overlap), opponent implied total for pitchers, and the 30-minute refresh cadence.

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?

Four sentences, each carrying distinct information (purpose, three views, refresh), with the primary purpose front-loaded. Slightly dense but no filler sentences; every clause earns its place.

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, the description does the work of describing returns (combined/pitch_mix/zone_overlap scores, opponent implied total, lineup ranking) and refresh timing, so an agent knows what comes back. It stops short of explaining how the team/player/limit filters interact, but is otherwise complete for a read-only scoring 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%, so the baseline is 3, but the description meaningfully expands the 'view' enum by explaining what each value returns (hitter scores, starter vulnerability, lineup ranking), which the terse schema text ('Default hitters.') does not. Team, player and limit are not elaborated beyond the schema, keeping it short of a 5.

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?

The description states a specific resource and outcome: it scores hitters against the opposing starter's pitch mix and zone locations, and enumerates three distinct views (hitters/pitchers/teams). This is far more specific than a tautology, but it never explicitly contrasts itself with similarly-themed siblings such as invoke_mlb_matchup, invoke_mlb_hitter_splits or invoke_mlb_pitcher_splits.

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 real guidance for choosing among the tool's own views (hitters is the default, pitchers covers vulnerability, teams ranks lineups) and implies 'today' freshness. However, it never says when to reach for this tool versus the many adjacent MLB matchup/split tools, so cross-tool selection is left to inference.

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