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

With no annotations, the description carries the full behavioral burden. It partially compensates by labeling the data 'Live' (implying real-time, non-cached reads) and by enumerating the returned fields, but it says nothing about rate limits, auth/payment requirements, caching freshness, or pagination behavior.

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 sentences, front-loaded with what the tool returns followed by the usage rule. Most content earns its place, though the explanatory aside about basis points ('which is the number that tells you...') is editorial padding that could be trimmed.

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?

There is no output schema and no annotations, so the description's field enumeration usefully stands in for a return-value spec, and the board-vs-symbol rule covers the main call pattern. However, for a five-parameter tool it leaves the filtering/pagination parameters undocumented and gives no safety, cost, or freshness context.

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 0%, so the description must compensate for all five parameters, but it only explains symbol (single market vs whole board). The roles of id, limit, category, and instrument are completely unexplained anywhere, leaving four of five parameters opaque.

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 verb and resource ('Live quotes for Polymarket Perps markets') and enumerates the exact data returned (index, mark, last, mid, OI, funding rate, basis). That is far more specific than the bare name. It never distinguishes itself from close siblings like x402-polyperp-funding, x402-polyperp-book, or x402-polyperp-markets, so an agent cannot tell which of the overlapping perp endpoints to pick.

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 clearly states the two usage modes: 'One call without a symbol returns the whole board; pass symbol to price a single market.' That is actionable context for the primary filter. It stops short of exclusions or naming an alternative (e.g. use the funding endpoint for historical funding), so it is not a full when/when-not treatment.

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