WritersLogic Verifiable AI Agent Hub Geo Distance API
The Geo Distance API from WritersLogic Verifiable AI Agent Hub — 1 operation(s) for geo distance.
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OpenAPI Specification
openapi: 3.2.0
info:
title: WritersLogic Verifiable AI Agent Hub Geo Distance 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: Geo Distance
paths:
/api/v1/geo-distance:
post:
operationId: geo_distance
summary: Great-circle and WGS-84 ellipsoidal distance between coordinates
description: 'Computes the haversine (IUGG mean-radius sphere) and Vincenty inverse (WGS-84 ellipsoid) distance in metres plus initial and final bearings for up to 100 coordinate pairs, and optionally checks a claimed distance within a tolerance. Vincenty is millimetre-accurate except for nearly antipodal pairs, where it does not converge: those pairs return vincentyMeters null, status unknown and the haversine value (up to about 0.5% off the ellipsoid). Does not geocode, route over roads, or account for altitude.
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/geo-distance
security:
- x402: []
- apiKey: []
requestBody:
required: true
content:
application/json:
schema:
type: object
additionalProperties: false
required:
- pairs
properties:
pairs:
type: array
items:
type: object
required:
- from
- to
properties:
from:
type: object
required:
- latitude
- longitude
properties:
latitude:
type: number
description: Degrees north, -90 to 90.
minimum: -90
maximum: 90
longitude:
type: number
description: Degrees east, -180 to 180.
minimum: -180
maximum: 180
to:
type: object
required:
- latitude
- longitude
properties:
latitude:
type: number
description: Degrees north, -90 to 90.
minimum: -90
maximum: 90
longitude:
type: number
description: Degrees east, -180 to 180.
minimum: -180
maximum: 180
claimedMeters:
type: number
description: Optional distance to verify, metres.
minimum: 0
maximum: 21000000
label:
type: string
maxLength: 80
description: Caller label echoed back.
maxItems: 100
minItems: 1
description: Coordinate pairs.
toleranceMeters:
type: number
description: Allowed difference for claimedMeters (default 1).
minimum: 0
maximum: 100000
claimBasis:
type: string
enum:
- vincenty
- haversine
description: Which distance claimedMeters is compared against (default vincenty).
example:
pairs:
- from:
latitude: 50.06632
longitude: -5.71475
to:
latitude: 58.64402
longitude: -3.07009
claimedMeters: 969954.166
label: Land's End to John o' Groats
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.'
results:
type: array
items:
type: object
properties:
label:
type: string
haversineMeters:
type: number
vincentyMeters:
anyOf:
- type: number
- type: 'null'
description: Metres, or null when Vincenty did not converge.
vincentyConverged:
type: boolean
vincentyIterations:
type: integer
initialBearingDeg:
anyOf:
- type: number
- type: 'null'
description: Degrees clockwise from north at the start; null for coincident points. Haversine bearing when Vincenty failed.
finalBearingDeg:
anyOf:
- type: number
- type: 'null'
description: Bearing at the end point (direction of travel), null when unavailable.
bearingBasis:
type: string
haversineMinusVincentyMeters:
anyOf:
- type: number
- type: 'null'
description: Spherical-model error, metres, or null.
claimOk:
anyOf:
- type: boolean
- type: 'null'
description: true/false when claimedMeters was supplied and decidable, else null.
engine:
type: string
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:
- Geo Distance
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