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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile needs no restating. Beyond that, the description adds two non-obvious behaviors: rank semantics (1 = allows the most) and an entitlement gate (window 'recent' requires Pro), which prevents a paid-endpoint failure loop. It stops short of noting ordering, pagination, or whether teams with no games are included.

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?

The trigger is front-loaded, then output shape, then the exclusion — a sensible order for an agent skimming. Every clause carries information, though the parenthetical-heavy single paragraph is dense enough that the Pro-window caveat is easy to miss on a fast read; a short clause break would improve scannability without adding length.

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?

For a read-only, single-required-parameter aggregation tool with no output schema, the description covers everything necessary: what is returned (per-game allowed by position group plus pace), how values are ranked, which league/position vocabularies apply, entitlement constraints, and the tool it should not be used for. No gap remains for correct selection and invocation.

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 goes past the schema by spelling out the valid position-group vocabulary per league and the Pro restriction attached to the 'recent' window value. Season defaults are also covered. It doesn't explain how 'position' interacts with the NBA pace column or whether omitting it returns all groups.

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 uses a concrete verb and resource: it returns what every NBA or NFL team allows per game to each position group, with league ranks. It names the exact output columns (NBA G/F/C with pace; NFL QB/RB/WR/TE) and explicitly separates itself from player-level matchup tools, so an agent can distinguish it from siblings without opening the 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?

The description opens with a triggering user-question pattern ('best matchups for centers', 'defenses vs TE') and closes with an explicit exclusion naming the alternative tool and its condition ('Not for one player's matchup (player_profile's next game)'). Both the when and the when-not are stated, not implied.

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