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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety is covered. The description adds useful behavior beyond that: rows are sorted and paginated locally, and filtering supports combinations up to three seasons and four grouping fields — real operational context for calling it.

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?

Two sentences, front-loaded with what is fetched before the filter/pagination detail. Efficient and free of filler, though the trailing 'Use mlb_discovery' note could be folded more tightly.

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 an output schema present and a fully documented 15-parameter schema, the description only needs to frame scope and behavior, which it does: it covers the data returned, filtering, local sorting/pagination, and the vocabulary helper. Adequate for an agent to call correctly.

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% and every parameter is documented in the schema itself (defaults, ranges, formats from mlb_discovery). The description only restates the filter categories generically, so it adds little beyond the schema — the baseline of 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?

States a specific verb (Fetch) and a concrete resource (Baseball Savant Pitcher Arm Angle rows and league averages), which distinguishes it from the many other mlb_statcast_* siblings by data domain. It does not explicitly name which sibling to use for adjacent arm metrics, but the resource is unambiguous.

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 one explicit routing hint ('Use mlb_discovery for exact values') for enum/vocabulary lookup, and enumerates the filter dimensions available. However it gives no guidance on when to prefer this tool over other Statcast arm-metric tools (arm_strength, arm_value, etc.), leaving the alternatives implicit.

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