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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered. The description adds operational context beyond the annotations: the 'field-comparator-value' filter shape, that sorting is local, and that pagination applies. It does not disclose rate limits or return shape, but the output schema covers returns.

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 tight sentences with the core purpose front-loaded and the supporting detail (filters, routing) following. Nothing is padded, though the middle clause packs several mechanisms 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 an output schema present and 100% parameter coverage, the description need not explain return values. It supplies the key dependency (mlb_discovery) and the filtering/sorting model, leaving little an agent would need that isn't already structured.

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 every parameter is already documented in the schema, establishing the baseline of 3. The description echoes the same concepts (season/team filters, comparator filters, sort, pagination) without adding format or constraint detail beyond what the schema provides.

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 verb and resource ('Fetch Baseball Savant batter or pitcher Percentile Rankings'), making the purpose immediately legible. It stops short of distinguishing itself from the many sibling statcast tools, though it does name mlb_discovery as a supporting lookup.

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?

It gives concrete usage context (filter by season/team, apply percentile filters, local sort, pagination) and explicitly routes the agent to mlb_discovery for the exact type-specific fields, teams, seasons, and comparators. No explicit when-not guidance is given relative to sibling tools, but the routing instruction is clear.

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