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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so safety behavior is covered structurally. The description adds useful behavioral context: the metric set returned and the season-defaulting fallback logic. It does not disclose scope edges, rate limits, or what happens when a player has no absence sample, which limits it to an adequate 3.

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 description is two tight sentences: the capability/metrics statement first, then the calling instructions. It is front-loaded and wastes little. The dense parenthetical metric list is justified for an analytics tool.

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 usefully enumerates what is returned, which covers most of the agent's needs. But it leaves the `side` selector unexplained and does not clarify how the teammate-comparison output is structured or scoped, so the definition is adequate rather than complete.

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 0%, so the description carries the full parameter burden. It explains the required `player` and the `season` default behavior, which adds real value. But the `side` parameter (an offense/defense enum) is never mentioned or explained anywhere, leaving one of three parameters entirely undocumented.

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 analytical resource — team offense with/without one player — and enumerates the exact output metrics (points, yards, EPA per play, success rate, pass rate) plus the teammate-usage deltas (targets, carries, PPR points). This is concrete and far from a tautology. However, it never differentiates itself from a very similar sibling like invoke_nfl_injury_vacancy, which an agent would need to disambiguate against.

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?

"Pass the player name. Defaults to this season, then last season." gives concrete calling guidance and fallback behavior, which is genuinely useful. But there is no when-to-use guidance relative to alternatives (e.g., injury_vacancy or player_index), and no stated prerequisites or conditions where this tool is the wrong choice.

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