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

With readOnlyHint/idempotentHint already declaring the safety profile, the description still adds real operational context: metered usage and delay tied to the connected account, a single bounded request with no polling or automatic retry, and the Affiliate 27 exclusion. The trailing 'No wagers, account changes or guarantee of returns' is boilerplate and adds little, which keeps this from a 5.

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 the opening sentence runs directly into the next clause with no punctuation, and the semicolon-separated constraint list reads as appended boilerplate. The final clause about wagers/account changes/returns does not earn its place in a read-only price-history 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?

An output schema exists, so return values need not be explained, and the annotations cover the safety profile; the description covers access/metering caveats and exclusion rules reasonably. What is missing is the one thing an agent most needs here: what distinguishes this history tool from the many sibling history and delta tools in the family.

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 low (the single `query` parameter carries no description), but the nested properties `to`, `from`, `main_line`, and `market_line_price_ids` are documented in-schema with format and max-50 constraints; only `limit` is undocumented. The description contributes the provenance rule for the IDs but says nothing about the time-range or main_line semantics, so it neither compensates nor detracts.

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 clause names a specific verb (Get) and resource (price history for market line prices), and the ID-scoped framing makes the object of the query unambiguous. However, it is essentially a restatement of the title and does nothing to separate itself from near-identical siblings such as v2GetMarketLineHistoryByEvent or v2GetMarketHistoryByEvent, so an agent cannot route on the description alone.

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?

'Use returned canonical IDs' implies the input comes from a prior call's output, which is genuine implied usage guidance, and 'never infer coverage from an empty result' tells the agent how to read a null-ish response. But there is no explicit when-to-use vs when-not, and no alternative is named despite several sibling history tools existing.

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