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

With readOnlyHint and openWorldHint already covering the safety profile, the description goes further: it names the upstream data source (ESPN public site JSON), declares UTC time semantics, specifies empty-list behavior for game-less days, and discloses the $0.002 USDC x402 charge with the important caveat that failed calls are not billed.

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 dense sentences front-load the resource and returned fields, then the operational facts (UTC, empty list) and the pricing caveat. Nothing is redundant and nothing is buried.

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?

The tool has an output schema, so the return shape needn't be restated, yet the description still previews the key fields. Combined with the payment disclosure and empty-result behavior, an agent has everything needed to decide to call it and interpret a null-heavy response.

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 coverage is 100% and the single optional parameter already documents the YYYY-MM-DD format and the 'yesterday UTC' default, so the schema does the heavy lifting. The description reinforces the one-date scope and UTC convention but adds no format or edge-case guidance (e.g. how future dates behave) beyond what the schema states.

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+resource combination (ESPN NBA scoreboard for one date) and enumerates what each record contains: away/home team, score, status, venue, current period. The league qualifier cleanly separates it from sibling scoreboards such as dev_espn_mlb_scoreboard or dev_espn_nhl_scoreboard without needing to open a 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?

Gives clear operating context: this covers exactly one date, defaults to yesterday UTC, and returns an empty list on days with no games. It does not name alternatives or state when to prefer a different tool (e.g. season stats or standings), so there are no explicit exclusions.

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