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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint, so the safety profile is covered. The description adds genuinely useful behavior beyond that: metered usage/access delay tied to the connected account, a single bounded request with no polling or retry, affiliate 27 exclusion, and the caveat not to infer coverage from an empty result.

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 purpose is front-loaded, but it is delivered as a run-on ('...for an event Returns recorded price changes...') followed by a long trail of compliance-style statements that read partly as boilerplate. Several sentences (no wagers, no account changes) do little to help an agent invoke the tool.

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-format detail is not required, and the annotations cover the safety profile. Combined with the access/metering, bounding, and empty-result caveats, this is close to complete; the main remaining gap is routing against sibling history tools.

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 schema coverage is reported as 0%, so the description should carry more weight, though the nested property descriptions are in fact rich (market_ids default/cap, affiliate_ids list, main_line semantics). The description only implicitly signals filtering by markets/sportsbooks, the affiliate 27 exclusion, and canonical IDs, adding little syntax or default detail beyond the schema.

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 opening sentence names a specific verb (Get) and resource (market price history for an event), which is unambiguous on its own. However, it does not differentiate from close siblings such as v2GetMarketLineHistoryByEvent or v2GetMarketLinePriceHistory, which an agent must disambiguate before choosing this tool.

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 contextual guidance about historical-data access being plan-dependent and prices being recorded before/during/after an event, and warns that empty results do not imply missing coverage. But it names no alternative tool and gives no explicit when-to-use-this-vs-sibling rule, which matters in a family containing several near-identical history endpoints.

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