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

Annotations already cover the safety profile (readOnlyHint=true, destructiveHint=false, openWorldHint=true), and the description adds genuine extras: it is free, requires no API key, and discloses that funding history is measured "since launch" for a long — a non-obvious data-scope trait. It stops short of saying anything about freshness, pagination, or failure modes for an unknown asset symbol.

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?

Three short sentences, front-loaded with the use case, then the return payload, then the filter. Every sentence carries content; only "Free, no key" is tersely telegraphic rather than a full clause, and it slightly overlaps with the title's field list.

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 two-param, no-required-argument read tool with an output schema, this covers what the agent needs: what the board contains, how to narrow to one perp, that no auth is required, and that the read is safe. Return-shape detail is legitimately delegated to the 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 both parameters (asset, limit) are already documented in the schema, including the 30-row clamp and default 25. The description's only param-level addition is repeating the asset examples ("btc", "gold"), which the schema already provides. 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?

The description names the specific resource (every Kalshi perpetual future) and enumerates exactly which fields the board returns — price, 24h volume, open interest, long/short max leverage, funding cadence, and cumulative funding cost since launch. The quoted query examples ("Kalshi perps funding rate", "how much leverage on Kalshi gold perps") make it immediately distinguishable from siblings like perp_liquidation or calculate_ev.

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?

It gives explicit trigger phrasing ("Use for ...") and states the single-asset mode ("Pass asset ... for one"), but it never names an alternative or an exclusion — nothing tells the agent when to prefer perp_liquidation, market_pulse, or commodity_edge instead. Clear context, no routing rules.

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