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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is covered. Beyond that, the description adds real behavioral context: no live data, flat volatility assumption, USD Black-Scholes Greeks, time-Greek sign convention (derivative w.r.t. time to expiry with sign flipped), a stated 1/365 definition of a calendar day, and the important failure mode that non-finite Greeks are an error rather than a null.

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 core purpose is front-loaded in the first sentence, which is good. However, the body is a dense run-on of semicolon-separated clauses with no structure, and it spends words restating input ranges that already appear verbatim in the schema properties. The long per-Greek units enumeration earns its place, but the block is harder to scan than it needs to be.

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, yet the description enumerates every returned field (price, delta, gamma, vega, theta, rho plus vanna, vomma, charm, veta, speed, zomma, color) and defines each higher-order Greek's unit and interpretation, including which are identical for calls and puts. Combined with the exclusion list and error behavior, an agent has everything needed to call it correctly and to explain the result.

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 the description largely repeats the schema's own bounds ('daysToExpiry 0.001 to 36500, volatilityPct 0.01 to 1000, ... riskFreeRatePct and dividendYieldPct 0 to 100') rather than adding to them. It does add that the dividend yield is continuous and applies to stocks and ETFs, but the per-parameter meaning is still carried mostly by the schema, so the baseline of 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 and resource: it returns first and second order Greeks of a European option priced with Black-Scholes-Merton from manual inputs. It positions itself precisely against siblings by describing itself as everything workflow.run_black_scholes returns plus the higher-order Greeks, and it names workflow.run_american_option as the tool for early exercise. An agent can distinguish it from the ~90 siblings 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 an explicit trigger ('Use when the user asks how delta changes when volatility or time moves... or for an option greeks calculator') and explicit exclusions ('Not covered: early exercise (use workflow.run_american_option), discrete dividends, a volatility smile, negative rates, Greeks of coin-settled options'). The 'manual inputs only (no live data)' clause also implicitly routes live-data requests to the _live siblings.

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