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

Annotations already establish readOnly/idempotent/non-destructive, so the burden is lower; the description nevertheless adds real behavior: a 30-minute data refresh cadence, the DraftKings scoring basis, the 1.5x captain projection multiplier, and the default slate selection. It omits pagination/limit interplay (the schema mentions a plan limit) and any failure behavior when a game has no showdown slate.

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 mode, then the field inventory, then the invocation rules and freshness note — every sentence carries information. The field list is dense but justifies its length by telling the agent exactly what comes back in the absence of an output schema.

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 no output schema, the description compensates well by enumerating the returned fields, and it covers targeting, defaults, scoring and refresh cadence. Remaining gaps are minor: no mention of how many rows are returned by default versus limit, and no cross-reference to invoke_nhl_list_slates for slate discovery (only the schema mentions it).

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%, so the baseline is 3; the description earns above baseline by clarifying that slate_id and game are alternative selectors and by documenting the no-argument default, which the schema does not express. It says nothing about the limit/plan-limit interaction or what include_out does beyond the schema text.

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?

The description names the specific resource and mode: a DraftKings NHL Showdown captain-mode pool for a single game, and enumerates what the response contains (salary, captain salary, projection, 1.5x captain projection, floor, ceiling, line, PP unit, DK ids). The 'for one game' + 'captain mode' framing implicitly separates it from invoke_nhl_player_pool, but no sibling is named explicitly, so it falls short of a 5.

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 tells the agent how to target the call ('Pass slate_id or a game like FLA@CAR') and supplies a documented fallback ('Default: the first showdown slate of the day'), which removes ambiguity about zero-argument invocation. It does not, however, state when to prefer this over invoke_nhl_player_pool or invoke_nhl_optimizer, so no explicit exclusions are present.

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