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

With no annotations, the description carries the full burden and discloses key behavior: this is a paid tool ($0.002 USDC on Base via x402), requires a two-step handshake, and specifies the exact mechanism (_meta['x402/payment']). It also describes the return format. It omits details like pagination, rate limits, or error handling, but the payment and return behavior is unusually well documented for a tool without annotations.

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 front-loaded with purpose and return information, then efficiently covers the essential payment flow. Every sentence earns its place, though the payment instructions are dense and could be slightly more scannable. It avoids redundancy and stays focused on what an agent needs to call the 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?

Given no annotations, no output schema, and a paid interaction model, the description is largely complete: it covers purpose, return contents, cost, network, and the payment handshake. It does not explain pagination, error behavior, or search nuances, but the critical behavioral and invocation details are present. Missing elements are minor for a two-parameter search tool.

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%, so both parameters (q and limit) are fully documented in the schema, including defaults, min/max, and meaning. The description adds no parameter-specific syntax or format details beyond what the schema provides. Baseline 3 is appropriate when 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 states a specific verb and resource: 'Search Polymarket prediction markets (V2)', and clarifies the return payload as 'events with market questions, volume and liquidity'. This distinguishes it from siblings like poly_odds, poly_signals, and poly_whales, which imply different resource types. An agent can immediately identify that this tool searches markets rather than retrieving odds or signals.

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?

The description explains the paid invocation flow (first call returns payment terms, retry with payment), but it does not state when to use this tool versus alternatives such as poly_odds or poly_signals. No conditions, exclusions, or sibling comparisons are provided. Usage is implied only by the resource name, not by explicit guidance.

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