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

Goes well beyond the readOnlyHint/openWorldHint annotations: discloses the data source (ESPN public site JSON), UTC timezone, empty-list behavior for off days, and — crucially — the paid-call model ($0.002 USDC via x402, failed calls free). That billing detail is exactly the kind of thing an agent must know 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?

Two sentences, front-loaded with what the tool returns, then delivery details and cost. No restated title or filler; 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?

For a single-parameter read tool with an output schema and clear annotations, nothing essential is missing — source, timezone, edge case, and payment terms are all covered.

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 already documents the single date parameter at full coverage, including the YYYY-MM-DD format and the 'yesterday UTC' default. The description reinforces the UTC framing and adds the no-games outcome, adding modest value on top of an already complete schema.

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?

Names a specific verb+resource+scope: 'ESPN NHL scoreboard for one date', and enumerates the returned fields (teams, score, status, stadium) plus the upstream source. An agent can tell it apart from the other dev_espn_* scoreboards by league alone.

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 one-date scope and the 'empty list on days with no games' rule give useful context, but there is no explicit routing guidance among siblings like dev_espn_sports, dev_espn_standings, or dev_hockey_reference. Usage is implied rather than stated.

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