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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds real value beyond that: the pre-game domain restriction, the two book sources compared, what each row contains, and a required disclosure when relaying results. It stops short of describing volume, ordering guarantees beyond the limit param, or how ties/absent books are handled.

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 the core definition and followed by row contents and the relay caveat. No filler, no restatement of the title, and the non-advice instruction is placed where it will be read.

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 10 parameters and no output schema, the description carries the return-shape burden and does so by enumerating row fields, plus it scopes the domain and adds the disclosure requirement. Minor gaps remain around pagination behaviour and what an empty result implies, but nothing essential for a correct call is missing.

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 schema already documents book, stat, limit, league, player, min_move, user_request, max_age_minutes, include_reverted and lookback_minutes. The description reinforces the semantics of a measured 'move in probability points' and the notion of a line that 'stayed', which underpins min_move and lookback_minutes, but adds no field-level detail the schema lacks.

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 a specific, distinctive resource: PrizePicks lines in NBA/NFL/NHL pre-game where the BetRivers or Kalshi price moved materially while the PrizePicks line stayed. It also enumerates the per-row fields (line, move in probability points, move time, staleness duration, observed_at for both sides), so an agent knows exactly what it gets and how this differs from a generic change feed or line-history sibling.

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?

Implicit usage is clear (surface stale PrizePicks lines relative to book movement) and the 'before the game' scope plus the 'information about prices, not a prediction or betting advice' relay instruction are useful constraints. However, it never says when to prefer this over siblings such as get_line_history, get_changes or compare_lines, nor any when-not conditions, leaving routing to inference.

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