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 a genuinely non-obvious behavioral trait: 'sorting and pagination are applied locally,' which tells the agent how ordering and paging behave. It does not mention rate limits or data freshness.

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 zero filler, and the core capability is front-loaded before the parameter-sourcing note and the sibling pointer. Every clause carries information.

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?

An output schema exists, so return values needn't be described. Combined with annotations covering safety and a fully documented schema, the description supplies enough context for correct invocation, though it could say more about local sorting semantics.

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 all seven parameters are already documented in the schema. The description references groups, metrics, and comparison years but adds no syntax or format detail beyond what the schema provides, warranting the baseline 3.

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 resource (statistical rows from Baseball Savant Year-to-Year Changes), and enumerates the four group types. The 'Year-to-Year Changes' framing distinguishes it from generic statcast siblings, though it does not explicitly contrast with the many other mlb_statcast_* tools.

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 prerequisite workflow: 'Use mlb_discovery for exact groups, metrics, and years,' naming the alternative and the condition that selects it. It stops short of stating when this tool should not be used versus other statcast endpoints.

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