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

With no annotations, the description carries the full burden and does it well: deterministic, no LLM, seconds per call, a non-existent keyed market is refused before payment, a free-text miss returns not_found with nearest candidates, informational-only disclaimer, and explicit pricing ($0.01/call via USDC over x402). These are exactly the behavioral traits an agent needs and none of them are restated from structured fields.

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 purpose and the output payload before commercial and error details, and nearly every clause earns its place. It is, however, one long run-on sentence with heavy comma chains, which slightly hurts scanability.

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 exists, and the description compensates by enumerating the returned fields and the error modes (not_found with nearest candidates, pre-payment refusal). Combined with the data source (Gamma API) and cost model, an agent has everything needed to call it correctly.

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 single 'market' parameter is already documented at 100% coverage in the schema, including the slug / 0x condition id / free-text forms. The description restates those forms but adds no new syntax, precedence rules, or formatting detail beyond it, so the schema does the heavy lifting and 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 verb and resource — the current odds of ONE Polymarket market and how they moved — and enumerates the returned fields (YES/NO prices, last trade, implied probability, liquidity, volume, 24h/7d change). The scoping word 'one' implicitly separates it from the multi-market sibling market_screener, so an agent can route without opening a 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?

It tells the agent how to address a market (slug, 0x condition id, or free-text question) and what happens on a miss (not_found with nearest candidates), which is useful context. But it never names when to prefer this over siblings such as odds_history, market_screener, or resolution_check, so selection guidance is implied rather than stated.

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