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

Annotations already cover the safety profile (readOnlyHint=true, destructiveHint=false, openWorldHint=false), so the bar is lower. The description nonetheless adds genuinely useful operational context the annotations lack: a concrete cost ('10 credits for up to 200 games'), the shape of each returned row, and a compliance constraint on how the price data may be used. It omits auth/error behavior, which keeps it from a 5.

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?

Purpose and scope are front-loaded in the first clause, and the compliance warning lands at the end where it belongs. The main inefficiency is re-listing all seven market values that the schema enum already declares, which is duplicated text.

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 6-parameter read tool with an output schema, a full annotation set and 100% schema coverage, the description supplies everything the schema cannot: purpose, cost, row semantics, and the usage restriction on price data. Nothing an agent needs to call it correctly 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 3 is the baseline. The description still adds meaning beyond the schema: it enumerates the human-readable market names matching the enum, explains bookmaker as 'one book's closing line instead of the median across books', and ties the 200-game ceiling to the credit cost.

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 verb and resource ('see how a player did against his prop line over time') and pins the scope precisely: one market, one row per game, closing/opening line, prices, actual result and over rate. That is distinguishable at a glance from get_player_game_log (raw stats) and get_player_props (current lines), even without naming them.

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?

Opens with an explicit 'Use to...' condition and adds a hard usage constraint (prices are market information; never compute stakes or recommend bets). It does not name alternative siblings or state when not to use it (e.g. for upcoming lines use get_player_props), so it stops short of full routing guidance.

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