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

Beyond the `readOnlyHint` annotation, the description discloses that rows are only a rolling ~20-row slice, not the full card, that `prematch_total` counts markets not rows, that only `OPEN` status is tradeable, and that history must be snapshotted by the caller. This is substantial behavioral context that prevents realistic misuse.

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?

The description is dense but every sentence earns its place: purpose, cross-reference, use cases, windowing caveat, tradeability, and exclusions. It is front-loaded with the core definition and organized so critical limitations come before broad exclusions.

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 no output schema, the description compensates by pointing to `get_live_fixtures` for shape, and it covers usage, data-window limitations, status tradeability, and persistence expectations. There are no significant gaps for an agent to safely invoke this tool.

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 `limit` and `sport` fully. The description reinforces the rolling-window semantics for `limit` but does not add significant meaning beyond the schema; baseline 3 is appropriate.

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 resource (pre-match rows from the FanLine Wire tape), states what they contain (upcoming markets with American prices), and distinguishes the tool from its sibling `get_live_fixtures` by explicitly noting `inplay false`. An agent can tell exactly what this tool returns and how it differs from related tools.

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?

It gives explicit intended use cases ('pre-game prices, model inputs and no-vig-style work on the FanDuel card') and clear exclusions ('not a bet-placement service, not a multi-book comparison, not an opening/closing-odds archive'). The reference to `get_live_fixtures` and `get_market_summary` also helps route the agent to alternatives.

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