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

Annotations already cover readOnly/idempotent/destructive, but the description adds real value beyond them: 'one bounded request, no background polling or automatic retry', metered/delayed usage tied to the connected account, the warning never to infer coverage from an empty result, and the affiliate 27 exclusion. These are non-obvious operational traits.

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?

Front-loaded with the core purpose, then operational caveats. A few sentences are dense (exclusions, metering, retry) but each carries distinct information rather than restating the name or schema.

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 high-complexity, nested-schema tool with an output schema and full annotations, the description covers purpose, the alternate-lines decision, metering/retry behavior, exclusions, and the empty-result caveat. Return values are handled by the output schema, so little 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?

Top-level coverage is 0% and the description only calls out include_alternates and the main-lines default. That adds meaning to the alternate-lines toggle, but line/side/limit/period/affiliate_ids semantics are left to the nested schema descriptions rather than being clarified or prioritized in prose.

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+resource: returns the best currently open sportsbook price for each matching event/market/participant selection on a sport date. It also positions itself against siblings by calling itself 'the collection form of the event best-line endpoint' and explaining it avoids one request per event.

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?

Gives clear context: use this bulk form instead of per-event requests, and states the default main-lines-only behavior plus the include_alternates=true switch. It does not explicitly name which sibling to use when only a single event is wanted, but the routing logic is inferable.

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