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

Annotations already declare readOnly, idempotent, non-destructive and open-world. The description adds genuinely new behavioral context beyond them: paid access at $0.05 USDC per call via x402 on Base, Ed25519-signed responses, and that search is server-side. It does not discuss rate limits or result caps.

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?

Front-loaded with the core capability, which is good, but the pricing/x402 detail is duplicated ('$0.05 USDC x402 Base' and '[x402: 0.05 USDC per call on Base]') and a JSON input example is inlined into prose, adding noise.

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 usefully enumerates the returned fields and discloses the payment and signing model, which is what an agent needs to call it safely. Only minor gaps remain, such as result limits and what an empty/ambiguous query returns.

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?

Only one optional parameter and schema description coverage is 100%, so the schema already carries the semantics; baseline is 3. The description's embedded '{"input": "bitcoin"}' example restates the schema example rather than adding syntax or matching rules.

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 verb (search) and resource (prediction markets), plus the cross-platform scope (Polymarket + Kalshi) and the returned fields (live prices, implied probability, volume, liquidity, end date, conviction). This clearly separates it from the sibling polymarket_trades, which implies a different resource.

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?

Gives an intended audience ('trading and forecasting agents tracking event odds') and example query domains, which implies when to reach for it. However, it never states when NOT to use it or which sibling to prefer for adjacent needs (e.g. polymarket_trades).

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