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

With no annotations, the description carries the burden and does notable work: it discloses paid access ($0.002 USDC per call via x402 on Base), the upstream data sources, the ranking metric, and the shape of returned data (implied probabilities, links). It does not cover rate limits, freshness/caching, or failure modes, keeping it below 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?

Two sentences, zero waste: the capability statement is front-loaded and the pricing/access constraint follows. Every clause carries information an agent needs.

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 no-annotation, no-output-schema, single-parameter tool, the description supplies sources, ranking, returned fields, and cost. Minor omissions (caching window, error behavior when payment fails) are the only gaps.

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% and the single 'limit' parameter is fully documented in the schema (1-50, default 10). The description adds nothing about the parameter, so the baseline 3 applies.

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 and scope: most traded open prediction markets across Polymarket and Kalshi, ranked by 24h volume, with implied probabilities and links. The 'top/ranked' framing distinguishes it in spirit from odds_search and odds_market, but neither sibling is named explicitly.

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 by 'most traded ... right now' — an agent can infer this is a discovery/browse tool rather than a lookup. There is no explicit statement of when to prefer it over odds_search or odds_market, and no exclusions or prerequisites beyond the payment note.

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