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 externally. The description adds only the scoping detail ('season, or across all years') and nothing about return format, pagination, or data freshness, which is a modest contribution above the structured fields.

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 primary purpose is front-loaded and the alternative-tool hint follows. 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 need not be explained, and annotations cover the safety profile. With 100% schema coverage and a clear sibling routing hint, the definition is nearly complete; only richer behavioral context (caching, error cases) would push it higher.

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% and both parameters (player_id, year) are fully documented in the schema, including the 9999/all-years sentinel and the default-season behavior. The description's mention of 'player ID and season, or across all years' merely echoes the schema, so the baseline 3 applies.

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 Arm Strength throw records') scoped to an individual player and season. It explicitly distinguishes itself from the sibling leaderboard tool by contrasting 'individual' records with 'leaderboard rows', so an agent can route correctly without opening either 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?

Names the alternative (mlb_statcast_arm_strength) and gives a reason to use it ('to find leaderboard rows and seasons'), which is a clear routing hint. It stops short of stating exclusions or prerequisites (e.g., that you must already know the player_id), so it falls just below fully explicit when/when-not guidance.

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