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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds genuine behavioral context beyond that: it returns a match verdict and the actual value when the figure does not match, and it scopes the check to one player. It does not specify matching tolerance/precision, a minor gap.

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?

Three sentences, each earning its place: purpose+scope, return behavior, and usage rule. The core action is front-loaded and there is no filler or repetition of schema content.

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?

There is an output schema, so return details need not be re-explained, and the annotations carry the safety profile. The description covers scope, metrics, and when to invoke the tool. The one meaningful gap is the lack of precision semantics (does 'matches' mean exact equality or tolerant rounding?), which matters for a verification tool but is not disabling.

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 100%, so the baseline is 3. The description adds meaningful framing beyond the schema by categorizing the metric choices into logical groups (per-game stats, schedule items like bye week, positional rank, and season totals) and by framing 'value' as a figure to verify rather than merely look up. This helps an agent reason about which metric enum value fits the user's request.

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 first sentence states a specific verb ('Check'), a specific resource ('DraftCall data for one player'), and a concrete scope ('points per game, games played, bye week, positional rank, or any season stat'). It also reveals the output behavior (matches vs. actual value), making it unmistakably a verification tool. It is clearly distinct from all siblings such as compare_players, get_rankings, or get_player.

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?

Explicit usage timing is given: 'Use this before quoting a figure from memory, and whenever a user asserts a stat.' This covers both proactive and reactive scenarios. It does not explicitly name alternatives or exclusions, but the tool's verification niche is so distinct from the siblings that the guidance is sufficient.

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