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

Annotations already declare readOnlyHint=true and openWorldHint=true, covering the safety profile. The description adds that rows are retrievable and expandable via a details sibling, which is useful, but does not disclose pagination behavior, rate limits, or return shape specifics beyond what the output schema likely provides. A 3 reflects some added value with annotations doing the heavy lifting.

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 no filler. The first sentence front-loads what the tool fetches and for whom; the second lists filters and routing, keeping the most important scoping constraint early.

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 the description needn't explain return values. Annotations cover the safety profile. The description covers the resource, entity scope, the main filter axes, where to get valid values (mlb_discovery), and how to expand player rows (mlb_statcast_home_runs_details). Nothing essential for a correct invocation is missing.

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 9 parameters are documented in the schema. The description lists the filter categories (season, team id, minimum home runs, adjusted/standard mode, local sort, pagination) which summarizes but does not add syntax, defaults, or enum details beyond what the schema already provides. Baseline 3 is correct when schema fully documents each parameter.

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 ('Baseball Savant Home Runs Tracking rows') and names the entity scope (batters or pitchers). This clearly distinguishes it from siblings like mlb_statcast_home_runs_details (which expands player rows) and mlb_discovery (used for exact filter values).

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 says to 'use mlb_discovery for exact values', which tells an agent where to resolve team ids, sort columns, and modes before calling this tool. It also indicates rows can be expanded via mlb_statcast_home_runs_details. There is no explicit 'when not to use' guidance, but the routing to two specific siblings is strong contextual guidance.

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