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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, openWorld), so the bar is lower. The description adds genuine context beyond them: it discloses what a result row contains, and that short-duration crypto markets are deliberately excluded — a non-obvious filtering behavior the agent could not derive from the schema.

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?

Three short sentences, front-loaded with what the tool returns, then the exclusion rule, then the complementary call. No filler or restated boilerplate; every sentence earns its place.

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, the description needn't explain return values, and annotations cover the safety profile, so the remaining burden is scoping and routing — both partly addressed. The one gap is the absence of a direct pointer to the skilled/smart-money sibling tools for filtered whale lists.

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 description coverage is 100% for both params ('min' = minimum trade size USD, 'limit' = 1-50 trades), so the schema already carries the semantics. The description's 'above a size you choose' loosely restates 'min' but adds no format or default detail, 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?

States a specific verb+resource: largest recent buys and sells across all Polymarket markets above a user-chosen size, and enumerates the returned fields. It implicitly distinguishes itself from the sibling get_skilled_whale_trades by noting it covers 'all markets' and that judging whether a whale is 'any good' requires a separate call, but it never names that sibling explicitly.

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 one clear scoping rule (5- and 15-minute crypto markets are filtered out) and a follow-up suggestion ('pair with /v1/wallet'), which is real guidance. However, there is no explicit when-to-use-this versus get_skilled_whale_trades or get_smart_money, leaving the agent to infer which whale-trade tool fits a given query.

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