Hermes Plant

OptionLens — Black-Scholes price & Greeks

options_price

Idempotent

OptionLens (x402-paid, $0.30): deterministic Black-Scholes price and full Greeks (delta, gamma, vega, theta, rho) for European calls/puts, with dividend yield, intrinsic/time value, and moneyness.

Input Schema

TableJSON Schema

Name	Required	Description
`spot`	Yes	Underlying price (> 0)
`payer`	No	Optional wallet/account identifier; stored only as a hash
`apiKey`	No	Free-tier / plan API key (hp_free_… or a pass key). Forwarded as X-API-Key so paid tools serve from your monthly quota with NO x402 wallet. Get a free key (250 calls/mo) at https://hermesplant.com/pricing.
`strike`	Yes	Strike price (> 0)
`channel`	No	Discovery channel or source tag
`campaign`	No	Campaign tag for downstream telemetry
`xPayment`	No	Raw X-PAYMENT proof from an x402-compatible wallet/client
`actorType`	No	Caller type for analytics: agent, human, synthetic, system, or unknown
`synthetic`	No	Mark this paid retry as an internal test/probe for analytics exclusion
`optionType`	No	Option type, 'call' or 'put' (default call)
`volatility`	Yes	Annualized volatility, e.g. 0.2
`riskFreeRate`	No	Annual risk-free rate, default 0
`timeToExpiry`	Yes	Years to expiry, e.g. 0.5
`dividendYield`	No	Continuous dividend yield, default 0
`paymentSignature`	No	x402 payment proof to forward as PAYMENT-SIGNATURE and X-PAYMENT on retry
`paymentIdentifier`	No	Optional x402 payment identifier for idempotency/retry correlation

Output Schema

TableJSON Schema

Name	Required	Description
`ok`	Yes	True when the upstream storefront call returned a 2xx response
`httpStatus`	Yes	Upstream HTTP status code
`paymentRequired`	No	True when the response is an x402 HTTP 402 payment challenge

TDQS

A4/5.0

Behavior4/5

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

The description discloses that the tool is deterministic and paid, which goes beyond the annotations (idempotentHint=true, readOnlyHint=false). It adds cost context and determinism, which are useful for the agent. There is no contradiction with the annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single, front-loaded sentence that includes the tool name, payment info, and core outputs. Every clause adds value with no fluff or redundancy.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a mathematically complex tool, the description covers the pricing model, option type, and outputs (Greeks, dividend yield, intrinsic/time value, moneyness). The presence of an output schema means return values need not be described. Minor gaps like default values for risk-free rate are left to the schema, but the description is sufficiently complete.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The input schema has 100% coverage for all 16 parameters, so the baseline is 3. The description mentions dividend yield and computed outputs (intrinsic/time value, moneyness), which adds some context beyond the schema, but it does not provide additional syntax or detailed parameter guidance. It slightly enhances understanding of the dividendYield parameter's role.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool computes Black-Scholes price and full Greeks (delta, gamma, vega, theta, rho) for European calls/puts. It uses a specific verb ('price') and resource ('OptionLens'), and the scope (European options) distinguishes it from sibling tools like bond_analyze or cashflowlens_analyze.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description implies the tool is for European options pricing and mentions it is paid ($0.30), but it does not explicitly state when to use this tool over alternatives or describe exclusion criteria. No sibling alternatives are referenced, so usage guidance is only implied.

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

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TDQS

A3.9/5.0

Disambiguation5/5

Each tool has a clear, distinct purpose. Financial tools (bond, cashflow, deal, options, portfolio, wallet, waterfall) each target a specific analysis type, email tools are batch vs single, and e-commerce tools are separate. No two tools could be easily confused.

Naming Consistency4/5

Most tools follow a noun_verb pattern (e.g., bond_analyze, emailguard_validate), but there is some inconsistency: some use verb_noun (get_product, list_products) and brand names like cashflowlens_analyze break the pattern slightly. Overall, it is still readable and mostly predictable.

Tool Count4/5

With 19 tools spanning finance, email, security, and e-commerce, the count is slightly high but reasonable for a pay-per-use server offering diverse deterministic analytics. Each tool serves a distinct function, and the number is not overwhelming.

Completeness4/5

The set covers major financial analysis types, email validation, and basic e-commerce operations. Minor gaps (e.g., no tool for portfolio rebalancing or more advanced email features) exist, but the core advertised services are well-covered.

Resources

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