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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the description focuses on what they don't cover: the upstream source, MLB copyright, and a per-success x402 charge of $0.002 with failed calls free. That pricing/auth context materially affects whether and how an agent invokes it; only the response shape is left unexplained, and an output schema exists.

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?

Three compact sentences: purpose first, then input/scope constraint, then licensing and payment terms. Every sentence carries distinct information, though the price/licensing sentence packs two unrelated facts together.

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 annotations, a 100%-documented three-parameter schema, and an output schema, the description covers the only remaining unknowns an agent needs: the data source, the no-game-feed boundary, and the cost model. Nothing critical is missing, though a hint about stat scope (regular season vs. postseason) would close the last gap.

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%, and the schema itself documents the hitting/pitching group, the YYYY season with a 2025 default, and the player id with an example. The description restates that the input is an MLB person id but adds no format or edge-case guidance beyond the schema, so the baseline 3 applies.

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?

Names a specific verb and resource: player season stats (hitting or pitching) plus bio, from statsapi.mlb.com. Explicitly scopes out the game feed, which separates it from scoreboard/play-by-play siblings like dev_espn_mlb_scoreboard, and the required MLB person id pins down the entity type.

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 scope line ('season stats only, no game feed') tells the agent what the tool will and won't answer, which implies when to call it. However, it never routes the agent among the many near-neighbors (dev_mlb_statsapi, dev_baseball_reference, dev_espn_mlb_scoreboard), leaving the choice to inference.

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