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

Annotations cover the read-only safety profile, and the description adds real value beyond them: cached reuse of snapshot data (no new upstream call), an explicit absence of a volume field with the reason, and a billing note (paid in USDC on Base). It stops short of describing pagination or rung ordering behavior beyond 'strike-sorted'.

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 purpose, then caveats and exclusions in a single dense block with no filler sentences. It is on the longer side, but nearly every clause carries routing, cost, or data-limitation information.

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?

An output schema exists, so return values need no explanation, and the description still covers the exclusion cases, caching behavior, a data limitation, and cost. An agent has everything needed to select and invoke 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 'underlying' and 'limit' are already documented in the schema (including the default 100 / max 500). The description confirms the underlying scope ('one underlying') but adds no syntax or semantics beyond the schema, making the baseline 3 appropriate.

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 — viewing one underlying's HIP-4 'above $X' binary markets as a strike-sorted ladder — and adds the concrete payoff (reading the implied price distribution). It clearly distinguishes itself from prediction.hip4_snapshot by output shape (ladder of rungs vs. grouped questions).

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?

Explicitly names when not to use it: multi-outcome mutually-exclusive groups should go to prediction.hip4_snapshot's grouped_questions, and Polymarket data is out of scope. It also tells the agent the data is shared/cached with hip4_snapshot, so there is no cost to calling both.

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