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

Annotations cover the safety profile (readOnlyHint=true, destructiveHint=false, openWorldHint=false), so the description's main added value is the disclosure of the three return fields (hedgeNotional, requiredMargin, estimatedFundingCost) — important since no output schema exists. It doesn't note assumptions such as default leverage or funding-rate behavior, so it is not fully rich.

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 tightly packed sentences: purpose first, usage triggers second, return values last. No filler, and the most decision-relevant content is front-loaded.

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 single-purpose calculation tool with no output schema, the description supplies the return shape and usage triggers, and annotations cover safety. It omits behavioral edge cases (e.g., what happens with omitted optional params or negative/zero spotSize), so it is nearly but not fully complete.

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% and each parameter (spotSize, leverage, hedgeRatio, fundingRatePct) has an inline description with units and defaults. The description adds no syntactic or semantic detail beyond the schema, 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 a precise resource: the short perpetual futures position size needed to hedge a spot holding. This is clearly distinguishable from generic siblings like run_position_sizing or run_liquidation_safety, which do not compute a hedge against spot.

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 concrete trigger phrasing ("how much should I short to hedge my BTC?", "what margin do I need for a 100% hedge?"), which tells the agent the user intents this tool serves. It stops short of naming when not to use it or pointing to an alternative sibling.

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