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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered. The description adds the window/scope defaults (season = last season's 20 games plus current; tonight = teams playing today grouped by game), which is useful behavioral context but not beyond that.

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 the resource and metric inventory, then the configuration options. It is a dense run-on sentence with heavy list nesting, but nearly every clause carries distinct information, so little is wasted.

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 read-only tool with no output schema, the description adequately conveys the returned metrics, their units (per 60, ranks out of 32) and the configurable dimensions. An agent has enough to invoke it correctly, though nothing is said about row cardinality or pagination interaction with limit.

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 50%, with team and limit documented in the schema and the two enum parameters (scope, window) carrying no schema description. The description compensates by defining what season/l10 and tonight/all actually mean, adding real semantic value for the undocumented enums.

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 resource (NHL team matchup heatmap) and enumerates exactly what it contains — per-60 rates and ranks out of 32 across 5v5 pace, offense, defense, power play and penalty kill. This level of specificity clearly differentiates it from siblings like invoke_nhl_corsi or invoke_nhl_line_matchups.

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 explains the effect and defaults of the window and scope settings, which is configuration guidance, but it never states when to choose this tool over a sibling (e.g. corsi or line_matchups). Usage is implied rather than contrasted with alternatives.

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