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 genuine value by enumerating the record contents (receiving OAA, throw outcome, base state, timing, coordinates) and explicitly stating what is excluded (3D skeletal visualization), which prevents a wrong expectation. It still omits pagination behavior and how results are ordered.

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, zero waste. The scope (per player id) and the returned fields are front-loaded, and the exclusion sentence earns its place by heading off a common mis-expectation.

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 carries full parameter documentation. For a 23-parameter read-only fetch the description is nearly complete; the only gap is no hint about pagination or how the required player_id is typically obtained.

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 fully documents all 23 parameters including defaults and value ranges. The description adds no syntax, format, or cross-parameter semantics beyond what the schema already provides, making the baseline 3 correct.

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 (individual First Base Receiving play records) scoped to a player id, and enumerates the returned fields. The word 'individual' implicitly distinguishes it from the aggregate sibling mlb_statcast_first_base_receiving without needing to open 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?

The description says what the tool returns but gives no when-to-use guidance, no mention of the summary sibling mlb_statcast_first_base_receiving as the alternative, and no prerequisites. The only exclusion noted ('3D skeletal visualization is not included') is about output scope, not tool selection.

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