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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds two genuine behavioral traits beyond that: the data comes 'from real positions' (provenance) and weekend queries return a perp's move since the close plus its record, implying different semantics when the underlying market is shut.

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?

Purpose and scope are front-loaded before the trigger examples, and there is no filler. The fragment 'Weekends, a stock's perp move since the close and its record' is syntactically awkward and takes a beat to parse, slightly weakening an otherwise tight definition.

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?

With no output schema, the enumerated fields (price, OI, funding, liquidation levels) usefully stand in for return-value documentation, and the read-only annotation covers safety. However, the single required parameter is left entirely undefined, leaving a real gap in how an agent should supply it.

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?

'Args: entity' merely restates the single schema property, which has 0% description coverage. The description never clarifies whether entity is a ticker, crypto symbol, commodity name, or an ID that must first be produced by resolve_entity — a meaningful ambiguity for a data-fetch tool.

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 (perpetual futures) and enumerates the exact payload (price, open interest, funding, liquidation levels) across ~30 venues. This is clearly distinguishable from sibling tools like get_filings, get_calendar, or get_congress_trades 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 explicit trigger phrasing with four concrete user-question patterns ('X funding rate', 'X open interest', 'where do X longs get liquidated', 'X perps this weekend'), which is strong when-to-use guidance. It stops short of naming when NOT to use it or which sibling (e.g., compare) to prefer for cross-entity questions.

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