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

Annotations cover only readOnlyHint and openWorldHint, yet the description adds materially important behavior not in structured data: the data is on-chain and signed, and each call costs $0.02 USDC via x402 on Base or Solana. Cost and payment-protocol disclosure is exactly the kind of detail an agent needs before invoking a paid endpoint, and it goes well beyond what the annotations provide.

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 purpose and returned fields are front-loaded in one dense sentence, followed by short, scannable fragments for filtering, data provenance, and pricing. The only waste is the boilerplate 'Not investment advice', which does not help an agent decide whether to call the tool.

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 fully specifies the return payload (fields, ordering) and adds the cost model, so nothing an agent needs to call the tool correctly is missing. The absence of pagination notes is minor given the 'every live market' scope and the two optional filter parameters.

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 carries the load and does explain both parameters: category as a filter, q as free-text search, and it lists the concrete category values (sports, price, ipo, policy_rate, awards). It falls short of full compensation because it omits the 'other' enum value present in the schema and never states what field q searches over.

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 resource and scope ('Every live Hyperliquid outcome (prediction) market') and enumerates exactly what each entry contains (title, category, deadline, implied-probability prices with 24h change, 24h volume). The 'Every live... most traded first' framing clearly marks this as a list/browse tool rather than a single-market lookup like the sibling outcomes_market, so an agent can place it without opening the 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?

The description implies the tool's role (browse all live markets, optionally filtered) and tells the agent how to narrow results via category and q. However, it gives no explicit when-to-use vs when-not-to-use guidance and never references an alternative tool, so the agent must infer routing from the sibling names alone.

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