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

Goes well beyond the readOnlyHint/openWorldHint annotations: it discloses the paid x402 model ($0.002 USDC per successful call across Base, Solana or Arc), that failed calls are not charged, and names the upstream source (ESPN's public stats API, with the note that stats.nba.com blocks automated access). That is exactly the cost/auth/upstream context an agent needs before invoking.

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?

Front-loaded with what the data is, then coverage/season rules, then pricing last where it belongs. The long stat enumeration is verbose but earns its place by letting an agent verify field coverage; a shorter, slightly grouped field list would read better.

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?

With an output schema present, return format needn't be described, and the definition covers source, cost, season range and season-type. Missing only edge behavior: what happens on empty results, unsupported seasons, or what default sort/page resolution is.

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 already 100%, so the baseline is 3; the description adds genuinely new information by stating the lower season bound (2003 to now) and clarifying that season means the year it ends (2026 = 2025-26), plus noting statistics come as both per-game and totals. It does not explain sort defaults or the qualifiedOnly semantics beyond what the schema says.

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 resource and access pattern: 'NBA player season statistics, sorted leaderboard', then enumerates the exact fields returned (team, position, points, rebounds, double-doubles, etc.). This makes it trivially distinguishable from game-level siblings like dev_espn_nba_scoreboard and from dev_wnba_stats, which covers a different league.

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 implies usage through scope details ('Regular season or playoffs, 2003 to now'), which tells an agent the tool is applicable for season-level player leaderboards, but it never states when to prefer it over alternatives such as dev_espn_nba_scoreboard for game results or dev_wnba_stats for the WNBA. No exclusions or routing guidance are given.

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