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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so safety is covered. The description adds two things annotations cannot: the 2-credit cost and the snapshot semantics (latest day, or latest on/before the supplied date), which materially affects how results should be interpreted.

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, zero filler: purpose and payload first, then the date-resolution rule and cost. Every clause carries information an agent needs before calling.

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?

An output schema exists, so return structure need not be described, and cost plus snapshot behavior are covered. However, for a 2-parameter tool, leaving the team filter completely undefined is a real completeness gap.

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 50%: date is documented in the schema and reinforced in the description with the on-or-before fallback rule. The team parameter is bare in the schema and unexplained in the description — it is unclear whether it filters players by team or selects a team-specific report.

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 the exact payload: player status, injury, and expected return, as of a snapshot date. No sibling covers injuries, so it is easy to place, though it never explicitly contrasts with get_player, which may also expose injury fields.

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?

"Use for the injury report" implies the trigger, and the parenthetical clarifies date defaulting to the latest snapshot on or before the given date. There is no when-not guidance and no mention of an alternative tool for historical injury data or per-player lookups.

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