Hermes Plant

Purchase with x402

purchase_with_x402

Purchase a one-time product via x402 (returns 402 challenge or fulfillment JSON). Call get_x402_manifest first, verify method/path/network/amount/payTo, then sign and retry with PAYMENT-SIGNATURE.

Input Schema

TableJSON Schema

Name	Required	Description
`slug`	Yes	One-time product slug (e.g. destructguard-pro)
`email`	No	Optional email for the order record
`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.
`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
`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

A4.4/5.0

Behavior4/5

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

The description discloses the 402 challenge/fulfillment behavior and the retry with PAYMENT-SIGNATURE, which goes beyond what annotations (readOnly=false, openWorld=true) state. It adds context about the protocol flow but does not cover permissions or rate limits. No contradiction with 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?

A single, information-dense sentence that opens with the core purpose and packs the necessary workflow into a compact instruction. 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?

Given an output schema exists and the description covers the return type and the full purchase-retry workflow, it is quite complete. Minor omissions include error cases and rate-limit details, but the essential behavior is well conveyed.

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

Parameters4/5

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

Schema covers 100% of parameters, so baseline is 3. The description adds procedural context (verify manifest fields, sign and retry), which clarifies the purpose of paymentSignature and places parameters in the x402 flow. This elevates it above the baseline.

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 action ('Purchase'), the object ('one-time product'), and the method ('via x402'), distinguishing it from sibling tools like get_x402_manifest and start_checkout. The parenthetical about return types further specifies the tool's unique role.

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

Usage Guidelines4/5

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

Provides explicit sequencing ('Call get_x402_manifest first... then sign and retry'), which is strong usage guidance. However, it does not explicitly state when not to use this tool or mention alternatives like start_checkout, so it falls short of a 5.

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.

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