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

With no annotations provided, the description carries the full burden and does well: it discloses the three upstream sources and their failure surface, that age_seconds is returned so staleness is visible (a genuine operational caveat), and that no orders are ever placed. It does not cover rate limits, authentication, or what happens if an upstream is unavailable, so it falls 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?

It is a single front-loaded paragraph that opens with what the tool is and then details sources, output fields, and parameter usage in order of importance. It is dense but every clause carries information; the em-dash enumeration is slightly heavy but not padded.

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 two-optional-parameter read tool with no annotations and no output schema, the description covers the returned fields (prices, bid/ask, spread, volume, liquidity, tick size, book levels, open interest, age_seconds) and the parameter formats, so an agent can call it confidently. The remaining gap is what happens when `market` is absent, which leaves a valid call shape unexplained.

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 0% and both parameters are type-only in the schema, so the description must compensate — and it does: `market` is documented as accepting a slug or 0x… conditionId, and `token` as selecting a specific outcome's order book. It does not state whether either parameter is required, mutual exclusivity, or default behavior when both are omitted, which matters given required=0.

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 action ('one normalized read of a Polymarket market') and enumerates exactly what is aggregated from each of three upstreams (Gamma prices/bid-ask/spread/volume/liquidity/tick size, CLOB top-3 book levels, Data API open interest). This clearly distinguishes it from siblings like x402-poly-price, x402-poly-clob, or x402-poly-markets without opening any schema.

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 states the use case (get a single normalized snapshot across sources rather than three separate calls) and an explicit exclusion ('never places orders'), which frames it as a read-only aggregation tool. However, it does not name sibling alternatives or say when a narrower tool like x402-poly-clob should be preferred instead.

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