Hermes Plant

BondLens — bond & loan analytics

bond_analyze

Idempotent

BondLens (x402-paid, $0.25): deterministic fixed-income and loan analytics. Bond mode solves price<->yield-to-maturity, duration, and convexity; loan mode (send principal+annualRate+termMonths) returns an amortization schedule.

Tool call template

This tool declares no required parameters. Add optional parameters from the input schema as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {},
    "name": "bond_analyze"
  }
}

Input Schema

Name	Required	Description
`payer`	No	Optional wallet/account identifier; stored only as a hash
`price`	No	Bond price; supply to solve yield
`yield`	No	Annual yield; supply to solve price
`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
`periods`	No	Periods to maturity
`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
`faceValue`	No	Bond face value (default 1000)
`frequency`	No	Coupons per year (default 2)
`principal`	No	Loan principal (selects loan mode)
`synthetic`	No	Mark this paid retry as an internal test/probe for analytics exclusion
`annualRate`	No	Loan annual rate, e.g. 0.06
`couponRate`	No	Annual coupon rate, e.g. 0.05
`termMonths`	No	Loan term in months
`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

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

Schema Changelog

Changes observed during successful MCP inspections.

Changed1 schema field changedJul 9, 2026
- removedInput schema / additionalProperties
```
Removed value: -false
```
Changed1 schema field changedJul 9, 2026
- addedInput schema / additionalProperties
```
Added value: +false
```
Changed1 schema field changedJul 4, 2026
- removedInput schema / additionalProperties
```
Removed value: -false
```

Changed1 schema field changedJul 4, 2026

addedInput schema / properties / apiKey

Added value: +{
+  "description": "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.",
+  "type": "string"
+}

Changed1 schema field changedJul 2, 2026
- addedInput schema / additionalProperties
```
Added value: +false
```
Changed1 schema field changedJul 2, 2026
- removedInput schema / additionalProperties
```
Removed value: -false
```

Changed1 schema field changedJun 29, 2026

changedOutput schema / (root)

Previous value: -nullNew value: +{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "additionalProperties": false,
+  "properties": {
+    "httpStatus": {
+      "description": "Upstream HTTP status code",
+      "type": "number"
+    },
+    "ok": {
+      "description": "True when the upstream storefront call returned a 2xx response",
+      "type": "boolean"
+    },
+    "paymentRequired": {
+      "description": "True when the response is an x402 HTTP 402 payment challenge",
+      "type": "boolean"
+    }
+  },
+  "required": [
+    "ok",
+    "httpStatus"
+  ],
+  "type": "object"
+}

Changed1 schema field changedJun 24, 2026
- addedInput schema / properties / actorType / description
```
Added value: +"Caller type for analytics: agent, human, synthetic, system, or unknown"
```
First observedJun 23, 2026

TDQS

A4.4/5.0

Behavior4/5

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

Annotations indicate idempotent, non-destructive, but not read-only. The description adds that it is 'x402-paid, $0.25' and 'deterministic', disclosing the payment side effect and predictable calculation behavior. 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?

Two sentences, front-loaded with the tool name and payment requirement, then concise mode descriptions. No filler or redundant restatement of schema properties.

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?

Covers both modes, the payment mechanism, and key input requirements. Output schema and 100% schema coverage fill in the remaining details. Slight gap: it doesn't explicitly state that bond mode requires either price or yield, but the price<->yield notation implies it.

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 coverage is 100%, so baseline is 3. The description adds mode-selection semantics by specifying which parameter combination triggers loan mode, and implies price<->yield either/or usage for bond mode, which is not explicit in the schema.

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 a specific purpose: deterministic fixed-income and loan analytics, with distinct bond mode (solving price/yield, duration, convexity) and loan mode (amortization schedule). This differentiates it from sibling tools like options_price 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 Guidelines4/5

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

It tells when to use bond mode vs loan mode by specifying required inputs (principal+annualRate+termMonths for loan mode). It doesn't explicitly exclude alternatives, but the mode-specific instructions provide clear usage context.

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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