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

With no annotations, the description carries the full burden and does disclose valuable traits: the tool is paid ($0.003) and the payment settles inline, and the data universe is capped at the ~500 most-traded markets, which tells the agent results are a bounded sample. It omits rate limits, pagination/ordering guarantees, and whether a failed payment still returns data.

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 dense sentence with the subject and scope front-loaded, then the returned fields and price. No filler; the parenthetical window option and the $0.003 cost are placed where they are needed.

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 and no annotations, but the description compensates by enumerating what comes back and naming the cost model. Remaining gaps are minor: default limit/window behavior and the fact that payment is required before a result set is returned are left to the schema.

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 100% — every parameter including the x402 payment payload is documented in the schema itself, so the baseline is 3. The description adds only marginal semantics (the 1h/1w windows, already in the enum) and says nothing about how limit interacts with the ~500-market universe.

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?

States a specific resource (Polymarket prediction markets), a specific operation (markets whose odds moved most), the ranking universe (~500 most traded), and the return fields (move, price, bid/ask, volume, link). This clearly separates it from prediction_odds (current prices) and hl_movers (a different venue's movers).

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 phrase 'moving now' implies the intended use case, and the 1h/24h/1w parenthetical hints at momentum-hunting, but no explicit when-to-use or when-not-to-use guidance is given. It never names prediction_odds or hl_movers as alternatives, so an agent must infer the routing decision.

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