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

Annotations already declare read-only, idempotent, non-destructive, open-world, but the description adds material context they cannot carry: Affiliate 27 exclusion, account-dependent access/delay/metered usage, single bounded request with no polling or automatic retry, and the explicit 'no wagers or account changes' guarantee.

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 operative content (what it returns, what it is not, canonical IDs, empty-result caveat) is front-loaded and dense. The trailing compliance sentence ('No wagers, account changes or guarantee of returns') reads as boilerplate that dilutes rather than informs, costing a point.

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-shape explanation is rightly omitted. The description covers the key behavioral caveats (empty results, affiliate exclusion, no retry) for a nested-object, single-required-param tool; only parameter-level filtering detail is thin.

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?

With schema description coverage reported at 0%, the description should compensate more than it does; it only touches parameters indirectly via 'Use returned canonical IDs' for eventID. It adds no guidance on participant_ids/participant_type filtering semantics, and notably does not resolve the schema's internal conflict (max 99 vs max 50).

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 and resource ('Get available markets for an event') and immediately delimits scope by ruling out prices ('not prices — use the event endpoint with market_ids for prices'). An agent can distinguish this from the many price/market-listing siblings without opening a schema.

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 when-to-use context (fetch market definitions per event) and an explicit when-not (prices belong to the event endpoint with market_ids). It also warns not to infer coverage from an empty result and to use returned canonical IDs. It does not name a concrete sibling tool, but the routing condition is unambiguous.

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