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 useful drill-down dependency context (row_id origin, filter mirroring) but says nothing about result size, pagination, or why the filters must match. Adds some value over annotations, but modestly.

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 tightly packed sentences, zero filler. The core action is front-loaded and the workflow guidance follows without redundancy.

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?

Output schema exists so return values need no explanation, and the schema documents all 22 parameters. The description supplies the drill-down workflow and filter-discovery pointer, making it essentially complete, though it could clarify what "same table filters" means for the optional params.

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?

With 100% schema coverage the baseline is 3, but the description adds meaning beyond the schema by instructing that the same table filters and type from the parent call should be passed, and by routing filter-value discovery to mlb_discovery. This is genuine parameterization guidance the schema does not contain.

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 ("per-swing Statcast play details and timing measurements") and explicitly ties itself to the sibling mlb_statcast_swing_timing by consuming its row_id. An agent can distinguish this drill-down from the parent list tool 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?

It gives clear workflow context: use a row_id returned by mlb_statcast_swing_timing, repeat the same table filters and type, and consult mlb_discovery for accepted filter values. It does not state any when-not condition, but the ordering relative to the parent tool is explicit.

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