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

Goes well beyond the readOnly/idempotent annotations by disclosing data coverage rules (opening and closing per book from July 2020; final pregame line only before that), credit costs per call shape, and derived fields (implied probabilities, favourite-won and over/under flags against the median close). It also states a policy constraint on how the data may be used, which no annotation conveys.

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 dense sentences, front-loaded with the payload then the invocation modes then the usage policy; nearly every clause carries information. The mid-sentence parenthetical about pre-July-2020 coverage is slightly awkward but earns its place.

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 shape need not be explained, and the description still covers coverage window, cost, derived fields and usage policy. Nothing an agent needs in order to call this 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 coverage is 67%, so the description usefully adds that game_id is single-game and date is a whole day, along with the differing credit cost of each path. The league parameter (enum, default mlb) is left entirely to the schema, so it does not compensate for the remaining coverage gap.

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?

Names a specific resource (betting lines) and enumerates exactly what is returned: each book's moneyline, run line and total, opening and closing, with implied probabilities. This clearly separates it from siblings such as get_line_movement (movement over time) and get_player_props (player-level markets).

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?

Explicitly routes the two retrieval modes: game_id for one game (5 credits) or date for a day's games (10 credits), and states a hard usage boundary (no stake/payout math, no bet recommendations, no sportsbook referral). It does not name a sibling alternative for cases where historical line movement is wanted, which keeps it from a 5.

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