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

Annotations already declare readOnlyHint=true, openWorldHint=false, destructiveHint=false, so the safety profile is covered. The description adds genuinely useful behavior beyond that: no live data fetch (pure manual-input computation) and the coin-denomination convention that divides price by spot. It stops short of noting edge cases (e.g. zero/negative time to expiry, vol validation), so not a 5.

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?

It is dense and front-loaded — the core purpose, the sibling routing, and the unit convention all appear before the return list. The final sentence is a long output enumeration, but since there is no output schema it earns its place; the prose is slightly heavy overall.

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?

No output schema exists, so the description usefully enumerates return fields and clarifies per-unit conventions (vegaPerPct per 1 vol point, theta per day, rho per 1 rate point) and USD vs coin quoting. Combined with annotations covering safety, an agent has enough to call it correctly; minor gaps remain around input validation/edge cases.

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 (spot, strike, daysToExpiry, volatilityPct, riskFreeRatePct) is already documented, including volatility units and the risk-free default of 0. The description restates the input set rather than adding new syntax or constraint detail, 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?

The description names a specific method (Black-Scholes), the exact resource (theoretical European option price and Greeks), and enumerates the output set. It explicitly distinguishes itself from run_black_scholes_live, so an agent can route between the two without opening either 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?

It states the concrete trigger ("what should this option be worth at X% IV?", raw Greeks for a hypothetical), the alternative (run_black_scholes_live), and the condition that selects the alternative (checking a real Deribit BTC/ETH instrument with a quoted price). When-to-use and when-not are both covered.

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