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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so safety is covered. The description goes further by enumerating the returned fields and giving a genuine edge-case disclosure (maxLossBound is non-null only for inverse/coin-margined shorts, includes the opening fee, null otherwise). That is real behavioral context beyond structured data, though it is buried in a dense sentence.

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 purpose sentence and return-field list are front-loaded and efficient, but the maxLossBound clause is a single ~70-word parenthetical with nested asides that is hard to parse and could be split or trimmed. Roughly half the description's weight sits in an over-stuffed sentence.

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?

There is no output schema, so the description correctly carries the return-value burden by naming grossPnl, fees, netPnl, netPnlUsdt, roe and maxLossBound. With annotations covering the safety profile and the schema covering all params, this is nearly complete; only the unwieldy maxLossBound phrasing weakens 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?

Schema description coverage is 100%, so every parameter (side, size, entryPrice, exitPrice, feeOpenPct, feeClosePct, contractType) is already documented with units and semantics. The description adds only one parameter-related fact (inverse PnL/fees are in base coin) which the schema also states, so the 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?

States a specific verb (calculate) and resource list (net PnL, ROE, fees, gross P/L) scoped to 'a futures trade', which distinguishes it from the sibling run_forex_pnl. An agent can identify the tool's function without opening the 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 an explicit trigger phrase ('what's my profit/loss on this trade?') that maps user intent to this tool. It does not name when-not-to-use or point at alternatives such as run_forex_pnl or run_breakeven_planning, so it stops short of full routing guidance.

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