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

With no annotations, the description carries the burden and does disclose the substantive contents the agent will get back, including the operationally important open-vs-cancel-only status and the fee schedule with volume tiers. It does not state that the call is read-only, whether it is cached, or whether the x402 payment/settlement layer applies, which keeps it short of a 5.

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?

A single sentence, front-loaded with the resource and followed by a compact enumeration of the returned facts. Every clause earns its place, though the colon-plus-list construction is dense and could be split for faster scanning.

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?

No output schema exists, so the description must stand in for return-value documentation, and it does so by naming the four categories of venue state. With zero params and no annotations, that covers what an agent needs to decide to call it, though the exact response shape and freshness/latency are unstated.

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?

The tool takes zero parameters, so the baseline is 4 and there is no parameter ambiguity to resolve. The description correctly stays silent on inputs rather than inventing them.

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 names a specific resource (venue-level exchange facts for Polymarket Perps) and enumerates exactly what is returned: order-acceptance mode, settlement chain/contract, engine version, and maker/taker fee tiers. It implicitly separates itself from data siblings like x402-polyperp-book or x402-polyperp-trades by being venue metadata rather than market data, but it never names a 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?

There is a clear situational cue: facts a bot needs 'before trading', which tells an agent this is a precondition/preflight call. However, there is no explicit when-not guidance and no named alternative (e.g. use x402-polyperp-markets for market listings), so the routing decision is left to inference.

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