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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds that sorting is 'local' and that pagination is supported, which is useful behavioral context, but it says nothing about response shape, auth, or rate limits.

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 the tool fetches, followed by the supported filter surface. The capability list is long but compact and free of filler, though it partially duplicates what the schema already enumerates.

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?

For a 15-parameter, all-optional tool with an output schema and read-only annotations, the description covers scope and the key dependency (mlb_discovery for accepted values) that the schema references but cannot resolve on its own. Return values are correctly left to the output schema.

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 15 parameters thoroughly. The description's grouping ('season/game filters, type-specific minimums, positions, team ids, dates, group dimensions') restates that surface without adding syntax, defaults, or format detail beyond the schema.

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 precise resource (Baseball Savant Fielding Run Value rows) and enumerates the five supported row types (fielder, fielding-team, batter, batting-team, pitcher). This clearly separates it from generic siblings like mlb_statcast_run_value, though it never names a sibling explicitly to confirm the distinction.

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 description implies its usage through the filter/type list and gives one concrete routing hint: 'use mlb_discovery for exact accepted values' for enum-like fields. However, it never states when to choose this tool over mlb_statcast_run_value or other Statcast siblings, so the agent must infer selection.

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