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

With no annotations, the description carries the full burden and does well: it discloses the pricing model ($0.01 per call from shop credits), the free-on-failure/empty behavior, the data sources, and a facts-only scope disclaimer. It does not cover rate limits or the exact auth mechanism beyond pointing at buy_credits, but the billing and failure semantics are high-value traits not present in the schema.

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-loads the purpose, then the disclaimer, then the cost model in three tight sentences. The disclaimer sentence is somewhat long but serves a real behavioral purpose; nothing is redundant with structured fields.

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 simple, all-optional-parameter listing tool with no output schema, the description supplies purpose, source coverage, sort order, and cost/failure behavior — enough for an agent to call it correctly. Only minor gaps remain (rate limits, return shape not needed since no output schema).

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 q, limit and window are already documented in the schema. The description adds context (sorted by volume, hours-to-close, 24h default window) but no syntax or format detail beyond the schema, 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 verb+resource: prediction markets closing soon, with scope (Polymarket AND Kalshi), sort order (by volume) and a computed field (hours-to-close). It clearly distinguishes the resource from generic market tools but does not name or differentiate from its pm_* siblings such as pm_gaps or pm_odds.

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 usage (markets about to close) and routes to buy_credits for key acquisition, but gives no explicit when-to-use / when-not or alternative selection guidance versus sibling tools like pm_odds or pm_gaps. Usage is left to inference.

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