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

Annotations already declare read-only, idempotent, non-destructive and open-world, and the description adds real substance on top: results do not guarantee the sportsbook will accept the exact betslip, an empty result does not imply lack of coverage, POST computes prices from existing public prices rather than submitting a bet, and affiliate 27 is excluded. These are genuine behavioral caveats an agent needs.

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 opening concatenates the title directly into the sentence ('Find Best Same-Book Parlay Price Returns sportsbooks...'), which is awkward and mildly confusing. The trailing claims are somewhat repetitive — 'No wagers, account changes' restates 'does not submit a bet' — costing some density.

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 an output schema present, return-value detail is unnecessary, and the description covers the safety profile, affiliate exclusion, retry/polling policy and empty-result caveat. The one missing piece is disambiguation from the very similar v2GetBestParlayBook sibling.

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 100%, so the schema already documents the body/legs/limit/affiliate_ids structure, including the affiliate-27 exclusion. The description adds no format or syntax detail beyond what the schema provides, so baseline 3 applies.

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 states a specific verb and resource: it returns sportsbooks that have every requested leg open, ranked by combined same-book price. That is concrete and actionable. However, it never distinguishes itself from the near-identically named sibling v2GetBestParlayBook, leaving the agent to guess which parlay-price tool to call.

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 operational guidance (use returned canonical IDs, one bounded request, no background polling or automatic retry, affiliate 27 excluded) but never says when to choose this tool over v2GetBestParlayBook or v1GetBestLineMulti. Usage is implied rather than routed.

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