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

Annotations already establish the safety profile (readOnly, idempotent, non-destructive), so the bar is lower. The description adds real behavioral value beyond that: it warns that OI only exists from collection start and that historical funding does not imply historical OI, and notes the response carries observation boundaries and sample counts.

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 dense sentences with no filler, and the most important content caveat (OI/funding mismatch) is front-loaded. Structure is efficient for the amount of information conveyed.

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?

The description gives useful return-shape hints but a five-parameter, zero-schema-coverage tool with no output schema needs parameter semantics that are absent. It is adequate on the data caveats but incomplete on how to drive the call.

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 0% and the description names none of the five parameters. 'Hourly candles' loosely gestures at resolution and 'observation boundaries' at from/to, but from, to, limit, marketId, and resolution are never explained, so the description fails to compensate for the documentation gap.

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 specific resources (OI/funding/premium observations, venue funding settlements, hourly candles), making the returned content clear. It does not, however, distinguish this retrieval tool from siblings like perps.board or perps.compare, leaving the agent to infer the boundary from name alone.

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?

There is no explicit when-to-use guidance and no mention of alternative tools. The caveats about OI collection start hint at data availability but do not tell the agent when this tool is the right choice versus perps.board or perps.rankings.

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