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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds no context on permissions, rate limits, or data freshness, and an output schema exists to cover the return shape, so it neither contradicts nor enriches the behavioral picture significantly.

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?

Reasonably short and front-loads the core purpose before parameter notes and the sibling pointer. Slightly choppy with inline 'id: Required' fragments that duplicate the schema rather than earning their 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?

For a read-only stats tool with a full output schema and annotations, the description covers purpose, a cross-reference for the group enum (mlb_discovery), and basic parameter notes. Completeness is adequate, though it does not explain stat_type or game_type options that the schema leaves open.

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 parameters are already fully documented. The description only repeats 'id: Required' and the end_date/start_date pairing, which is already stated in the schema for both fields; it adds no enum values or format details beyond structured data.

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 ('Returns one player's MLB season statistics'), scoping to a single player and one season. It also names a sibling (mlb_player) for identity lookup, letting an agent distinguish this stats tool from the player-lookup tool.

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?

Provides a clear routing rule ('Use mlb_player to get an MLB player') so the agent knows this tool is for stats after resolving identity. However, it does not distinguish itself from other stats-oriented siblings like mlb_league_stats or mlb_team_stats, leaving some ambiguity.

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