HIP-4 prediction markets (questions, active & settled outcomes)

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

Annotations already cover safety (readOnlyHint, openWorldHint), so the bar is lower, and the description adds real behavioral context: it discloses the slim-row field set, the default sort (volume24h desc), the meaning of yesMark/noMark as implied probability, and that full=true returns descriptions. It omits any pagination or rate-limit caveat, keeping it from a 5.

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 page and its sections are front-loaded, and every clause carries information (section semantics, defaults, sibling pointer). It is dense and parenthetical, though, reading as one long run-on rather than cleanly separated points, which costs it a point.

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 an 11-parameter tool with no output schema, the description compensates well by enumerating the returned row fields and explaining defaults and section behavior. It is nearly complete, missing only explicit mention of limit/offset paging interaction and category filtering semantics.

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 a 3 is the baseline, but the description adds genuine meaning beyond the schema: section semantics, the sortBy default, the yesMark implied-probability interpretation, and settledLimit behavior. The fields/search parameters are left to the schema, which already documents them adequately.

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 ('HIP-4 prediction markets' with an enumerated set of sections) and explicitly routes the candle use-case to the sibling flowscan_hip4_outcome. An agent can distinguish it from flowscan_hip3_markets and flowscan_hip4_outcome without opening any 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?

Gives clear context for each section ('active' default, 'settled' with settleFraction, 'questions', 'all') and names the alternative tool for candles. It does not, however, state exclusions or contrast itself against the other market-listing siblings (hip3_markets, perp_markets), so it stops short of full when/when-not guidance.

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