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

No annotations are provided, so the description carries the full burden. It does describe the returned microstructure, which signals a read-only data fetch and conveys the behavioral intent (pre-trade fill-quality check). However it omits latency, caching, rate limits, market-coverage limits, and any failure modes.

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?

Front-loaded with purpose, followed by the returned fields and a one-line rationale; three sentences with little waste. The trailing coverage sentence about equities/indices/commodities is somewhat tangential to a prediction-market tool but not egregious.

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 usefully explains the return values the agent will receive, which is a real strength. But it leaves all four parameters undocumented and provides no behavioral/operational context, so it is not fully complete for a financial data 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 0% across four undocumented params (id, depth, symbol, instrument). The description hints that one 'market' is addressed and mentions asset classes (equities, indices, commodities, crypto) that loosely map to 'instrument', but it never explains id vs symbol, or what 'depth' controls.

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?

Specifies a concrete verb+resource: a 'Level-2 order book for one Polymarket Perps market,' and enumerates its contents (best bid/ask, spread, midpoint, cumulative depth, imbalance). This is enough to distinguish it from a top-of-book or quote tool, though it never names the close siblings like x402-polyperp-quotes or x402-poly-depth.

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?

Usage is implied rather than stated: 'the microstructure a trading agent needs before sending an order' and 'how you spot a bad fill in advance' suggest when to call it. There are no explicit alternatives, prerequisites, or when-not-to-use conditions, so the agent must infer routing.

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