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

Annotations only cover read-only and open-world hints; the description goes well beyond them. It discloses that closed markets are omitted, the upstream source (Polymarket Gamma API), a per-call price of $0.002 USDC paid via x402 across Base/Solana/Arc, that failed calls are not charged, and a financial-advice disclaimer. Those payment and filtering behaviors are not derivable 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?

The purpose and output shape are front-loaded in the first sentence, with pricing and disclaimer trailing. It is dense but every clause carries information; the only slight bloat is the legal/boilerplate tail.

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?

Output schema exists, so return-value explanation is not required, yet the description still summarizes it. With read-only/open-world annotations, a disclosed data source, pricing model, and closed-market exclusion, an agent has everything needed to call this 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?

Schema description coverage is 100%, so the baseline is 3. The description adds only marginal meaning, clarifying that 'q' is search words and 'slug' selects a single market as an alternative mode; the limit range and defaults live entirely in the schema.

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: fetch active Polymarket prediction markets by search words or by slug, and enumerates the returned fields (question, outcome prices as implied probability, volume, liquidity, end date, link). The scope is clear and the exclusion of closed markets sharpens it. It does not, however, differentiate itself from siblings such as pm_search, pm_event, or pm_resolved, which an agent must otherwise disambiguate on its own.

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 explains the two invocation modes (search words vs. a single slug) but gives no when-to-use guidance, no prerequisites, and no routing against the many neighboring pm_* tools. An agent is left to guess whether prediction_polymarket or pm_search is the right entry point.

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