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

Annotations already cover the safety profile (readOnlyHint, openWorldHint), so credit goes to the added context: it discloses the paid x402 model with an exact price ($0.006 USDC per call) and enumerates the returned fields. It does not mention rate limits, failure modes, or pagination, but the cost disclosure is genuinely decision-relevant information the annotations do not carry.

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 dense sentences with zero filler: identity first, usage modes second, return contract and cost last. Every clause carries information an agent cannot get from the schema or annotations.

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 no output schema, the description correctly compensates by listing the returned fields (implied probability, 24h/total volume, liquidity, end date, link), and it covers the paid-call cost and the two-parameter no-required-input surface. Missing only edge behavior such as what an empty topic match returns or result pagination beyond 'limit'.

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%, with 'q' documenting the topic examples and the omit-for-top behavior and 'limit' documenting the 1-50 range and default, so the schema does the heavy lifting. The description's 'search any topic' phrasing adds no syntax or format detail beyond that, so this sits at the baseline 3.

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 resource and domain ('Live prediction market odds from Polymarket') plus its two retrieval modes (topic search vs. top markets), which is enough for an agent to know what it gets back. It does not name or differentiate from the close siblings predictions_book and predictions_positions, so a routing agent still has to guess which of the three applies.

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?

'search any topic or get the most-traded markets' implies the two usage modes, and the q parameter repeats the omit-for-top rule. There is no explicit guidance on when to prefer this over predictions_book (order book depth) or predictions_positions (user positions), so selection is inferred rather than stated.

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