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

With no annotations, the description carries the full burden and does disclose two non-obvious behaviors: the x402 paid model ($0.02/call or subscription) and the exact result ordering (24h volume within each venue, interleaved). It does not cover what happens on missing/failed payment or whether results are paginated beyond limit.

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 tight sentences with zero filler. Minor deduction: the cost/payment notice is front-loaded ahead of the actual purpose, which delays the agent's identification of what the tool does.

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?

Sources, ordering, filters, and payment model are all covered for a 4-param read tool with no output schema. The remaining gap is that no return fields are described and there is no output schema to compensate, so an agent cannot anticipate the response shape.

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 limit, venue, contains, and access_token are all documented in the schema itself. The description only restates the filtering capability, adding no syntax or format detail beyond the schema; 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 (live open markets) with both named sources (Polymarket, Kalshi) and a defined ordering rule (24h volume per venue, interleaved). This distinguishes it from siblings like search_markets or market_lookup, though no 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?

The description implies usage via 'Filter by venue or text' and the volume-ranked live listing, but never says when to choose this over search_markets, market_lookup, or top_movers. With 11 siblings, an explicit routing hint would materially help.

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