The Formula Weight API from WritersLogic Verifiable AI Agent Hub — 1 operation(s) for formula weight.
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openapi: 3.2.0
info:
title: WritersLogic Verifiable AI Agent Hub Formula Weight API
version: 2.0.0
description: Pay-per-call agents settled in USDC on Base via x402. Every response carries a signed provenance envelope.
contact:
name: WritersLogic
url: https://writerslogic.com/agents
email: agents@writerslogic.com
servers:
- url: https://agents.writerslogic.com
tags:
- name: Formula Weight
paths:
/api/v1/formula-weight:
post:
operationId: formula_weight
summary: Formula weight from a chemical formula (Hill notation, IUPAC/CIAAW weights)
description: 'Parses a chemical formula (parentheses, brackets, hydrate dots such as CuSO4·5H2O, an ignored charge) for a chemist or an agent that must check a molar mass, and returns the Hill-notation formula, the formula weight in g/mol from the CIAAW abridged standard atomic weights summed exactly in decimal arithmetic, and mass fractions. Pass claimedWeight and tolerance to check a stated molar mass. Elements with no standard atomic weight (technetium, promethium, elements above bismuth except thorium, protactinium and uranium) return unknown unless you supply elementWeights. A separate mode validates SMILES syntax against the OpenSMILES grammar. It does NOT compute a weight from SMILES, handle isotope or deuterium notation, or check that a compound exists.
Price: 0.005 USDC on Base (x402).'
x-x402-price-usdc: '0.005'
x-x402-amount: '5000'
x-payment-info:
protocols:
- x402
price:
mode: fixed
currency: USD
amount: '0.005'
x-audience: business
x-sample-url: https://agents.writerslogic.com/api/v1/samples/formula-weight
security:
- x402: []
- apiKey: []
requestBody:
required: true
content:
application/json:
schema:
type: object
additionalProperties: false
required: []
properties:
mode:
type: string
enum:
- formula
- smiles
description: formula (default) computes the weight; smiles validates syntax only.
formula:
type: string
maxLength: 200
description: 'Chemical formula, at most 200 characters. Element symbols are case-sensitive (Co is cobalt, CO is carbon monoxide). Hydrate separators: . · • *. A trailing charge such as ^2+, 2- after a bracket, or a bare + or - is ignored.'
smiles:
type: string
maxLength: 200
description: A single SMILES string without a name, at most 200 characters (mode smiles).
elementWeights:
type: array
items:
type: object
properties:
symbol:
type: string
maxLength: 3
description: Element symbol.
weight:
type: number
description: Atomic weight to use, g/mol.
minimum: 0.0001
maximum: 1000
required:
- symbol
- weight
maxItems: 20
description: Caller-chosen weights; they take precedence over the table and are the only way to weigh elements without a standard atomic weight.
claimedWeight:
type: number
description: Stated molar mass to check, g/mol.
minimum: 0
maximum: 1000000000
tolerance:
type: number
description: Allowed absolute difference from claimedWeight in g/mol. Default 0.01.
minimum: 0
maximum: 1000
example:
formula: CuSO4.5H2O
claimedWeight: 249.677
responses:
'200':
description: Paid result with provenance
content:
application/json:
schema:
type: object
properties:
data:
type: object
properties:
status:
type: string
enum:
- pass
- fail
- unknown
- unsupported
description: 'pass: every rule held. fail: a rule was violated (see witnesses). unknown: the input lacks the evidence to decide. unsupported: outside what this engine covers. Missing evidence is never a pass.'
mode:
type: string
enum:
- formula
- smiles
valid:
type: boolean
description: Whether the input parsed.
formula:
anyOf:
- type: string
description: Hill-notation formula of the whole input; null when it did not parse.
- type: 'null'
weight:
anyOf:
- type: string
description: Formula weight in g/mol rounded to 3 decimals; null when not computed.
- type: 'null'
weightExact:
anyOf:
- type: string
description: Unrounded decimal sum of the table weights; null when not computed.
- type: 'null'
uncertainty:
anyOf:
- type: string
description: Worst-case sum of count x table uncertainty in g/mol; null when not computed or caller weights were used.
- type: 'null'
chargeIgnored:
anyOf:
- type: string
description: The charge suffix that was stripped; null when none.
- type: 'null'
missingElements:
type: array
items:
type: string
composition:
type: array
items:
type: object
properties:
symbol:
type: string
count:
type: string
atomicWeight:
anyOf:
- type: string
- type: 'null'
mass:
anyOf:
- type: string
- type: 'null'
massFraction:
anyOf:
- type: string
description: Fraction of the total mass, 6 decimals.
- type: 'null'
parts:
type: array
description: 'For hydrates/adducts: each dot-separated part with its coefficient and weight.'
items:
type: object
properties:
text:
type: string
coefficient:
type: string
formula:
type: string
weight:
anyOf:
- type: string
- type: 'null'
smiles:
type: object
description: Counts from the SMILES syntax check (mode smiles).
properties:
atoms:
type: integer
bracketAtoms:
type: integer
ringClosures:
type: integer
components:
type: integer
witnesses:
type: array
items:
type: object
properties:
ruleId:
type: string
detail:
type: string
path:
type: string
description: JSON pointer or dotted path into the input.
offset:
type: integer
index:
type: integer
expected:
description: What the rule required.
actual:
description: What the input had.
versions:
type: object
description: Every semantic dependency of this answer (engine, tables and their as-of dates, tokenizer, calendar, rounding profile).
limits:
type: array
items:
type: string
deterministic:
type: boolean
description: 'Always true: pure code, no model.'
_provenance:
type: object
description: C2PA-aligned manifest and W3C VC 2.0 (eddsa-jcs-2022) issued by the hub DID; verify at POST /api/v1/verify-provenance
required:
- data
- _provenance
'400':
description: Invalid request (no payment consumed)
content:
application/json:
schema:
type: object
properties:
error:
type: string
code:
type: string
'401':
description: Invalid X-API-KEY
content:
application/json:
schema:
type: object
properties:
error:
type: string
code:
type: string
'402':
description: Payment required or invalid
content:
application/json:
schema:
type: object
description: x402 v2 PaymentRequired (also base64 in the PAYMENT-REQUIRED header)
properties:
x402Version:
type: integer
error:
type: string
code:
type: string
resource:
type: object
accepts:
type: array
items:
type: object
extensions:
type: object
'502':
description: Upstream failure; the payment is released or not settled
content:
application/json:
schema:
type: object
properties:
error:
type: string
code:
type: string
tags:
- Formula Weight
components:
securitySchemes:
x402:
type: apiKey
in: header
name: PAYMENT-SIGNATURE
description: x402 v2 payment payload (base64) sent after a 402 challenge
apiKey:
type: apiKey
in: header
name: X-API-KEY