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 real behavioral context beyond them: search, sort, and pagination execute locally rather than server-side, which changes how an agent should size its queries. It does not mention rate limits or caching, keeping it from a 5.

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. The resource is stated first, then the operational guidance, so the most important information is front-loaded.

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 need no explanation, and the schema covers every parameter. The description supplies the discovery pathway and the local-processing note, leaving only minor gaps such as whether seasons must be contiguous or how large a board response can be.

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 the schema already documents all 19 parameters including board, n, sort, and limit. The description adds only the instruction to pass board and to source filter values from mlb_discovery, which is marginal beyond the schema. Baseline 3 is appropriate.

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 names a specific verb ("Fetch") and resource ("Baseball Savant Baserunning Run Value, Basestealing, or Extra Bases Taken tables"), which precisely identifies which of the many statcast sibling tools this is. An agent can distinguish it from mlb_statcast_running_game or mlb_statcast_fielding_run_value without opening any schema.

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 clearly routes the agent: pass a board, and consult mlb_discovery for board-specific groups, thresholds, filters, and sortable fields. That is actionable context. It stops short of stating when NOT to use this tool versus adjacent statcast siblings, so it is a strong 4 rather than a 5.

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