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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint, and destructiveHint=false, so the agent knows this is a safe, idempotent read. The description adds scope (single game, coverage years, filters) but does not add behavioral context beyond what the structured fields and annotations provide, such as pagination, rate limits, or what 'no_play' rows represent.

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 a single dense sentence listing fields, followed by a short filtering note and a cross-reference. It is front-loaded with the core purpose and contains no filler.

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?

Given a four-parameter tool with full schema coverage and no output schema, the description is nearly complete: it states scope, coverage years, available filters, and where to find game ids. It could specify that data is in nflverse format or note any caveats about missing seasons, but overall it is sufficient for correct 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 description coverage is 100%, with all four parameters fully documented, including the game_id format, quarter range, and enum values. The description only reiterates that filtering by quarter or play type is possible; it adds no new meaning beyond the schema, so the baseline of 3 is appropriate.

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 and resource: 'Every play of one NFL game from nflverse play-by-play (1999–current)', then enumerates the exact fields returned. This clearly distinguishes it from siblings like nfl_schedule or nfl_player_season_stats.

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 says 'Filter by quarter or play type' and routes the agent to nfl_schedule for game ids. It provides clear context but does not name conditions where a different sibling (e.g., nfl_team_game_log) would be a better alternative.

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