Live prediction market odds, implied probabilities and betting-market data from Polymarket — give a market id or slug, get each outcome with its probability (0-1), volume, liquidity and resolution status. Price: $0.05 per call (x402 payment, USDC on Base mainnet).
| Name | Required | Description | Default |
|---|---|---|---|
| market | Yes | Polymarket market id or slug, e.g. '2654605' or 'will-it-rain-tomorrow' |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden. It honestly discloses the pricing model and payment method ($0.05 per call, x402 payment, USDC on Base mainnet), and clarifies that data is live. It does not mention rate limits or error behavior, but the payment disclosure is a significant behavioral trait beyond the schema.
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?
The description is two sentences, front-loaded with the core purpose and ending with actionable pricing/payment info. Every clause adds value, with no redundancy or filler.
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?
The tool is simple (one parameter, no output schema), and the description covers input requirements, output contents, and cost. It lacks a detailed output structure or error-handling info, but for a lightweight data-retrieval tool the description is sufficient.
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 schema has 100% coverage for the single 'market' parameter, including examples. The description essentially restates 'give a market id or slug' without adding further syntax or format details, so it does not go beyond what the schema already provides.
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 states a specific verb+resource: get live prediction market data from Polymarket. It clearly lists the output components (probability, volume, liquidity, resolution status) and distinguishes this tool from the crypto/sanctions-focused siblings by naming the unique data source.
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 description provides clear context on what to supply (market id or slug) and what to expect in return. It does not explicitly mention alternative tools or exclusions, but none of the sibling tools offer comparable Polymarket data, so the usage context is sufficient.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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