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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, covering the safety profile. The description adds valuable behavioral context beyond that: the per-call cost ($0.005 USDC via x402), the payment challenge behavior on unpaid calls, and the guarantee that no-data calls are never settled. This is exactly the kind of extra transparency that annotations do not capture.

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 description is four sentences, each carrying distinct information: purpose and fields, use case, cost/payment behavior, and HTTP route. It is front-loaded with the core purpose and avoids redundancy. Slightly verbose for a simple tool, but every sentence contributes value.

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?

For a read-only tool with two parameters and no output schema, the description covers the essential operational aspects: what it returns, how it is used, cost, payment failure mode, and an equivalent HTTP endpoint. It lacks explicit error handling or rate-limit info, but given the annotations and schema, this is sufficiently complete.

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 coverage is 100%, with both 'limit' and 'market' already described in the input schema. The description reinforces that 'market' is the condition id and notes it is required (though schema marks it optional), but it does not add new semantic meaning beyond the schema. The baseline of 3 is appropriate because the schema does the heavy lifting.

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 description clearly states the tool retrieves recent public trade prints for a single Polymarket market identified by condition id, and enumerates the exact fields returned (timestamp, side, outcome, price, size, notional, pseudonym, wallet, hash). This distinguishes it from sibling tools like polymarket_market (single market details) and polymarket_markets (listing markets).

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 provides a concrete use case: 'Use it to see whether a quoted price is actually trading and who is behind the flow.' This tells the agent when to employ this tool, though it does not explicitly mention alternatives or exclusion conditions. The context is clear enough to route correctly among the Polymarket family.

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