WritersLogic Verifiable AI Agent Hub Chat Fast API
The Chat Fast API from WritersLogic Verifiable AI Agent Hub — 1 operation(s) for chat fast.
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OpenAPI Specification
openapi: 3.2.0
info:
title: WritersLogic Verifiable AI Agent Hub Chat Fast 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: Chat Fast
paths:
/api/v1/chat-fast:
post:
operationId: chat_fast
summary: Chat completion, fast tier (8k in, 1k out)
description: 'OpenAI-style chat completion served by the hub''s provider router (small, fast model, up to 8000 input tokens and 1024 output tokens per call), with a signed receipt that binds the provider, model, token usage and the hashes of your messages and the reply. Supports optional strict json_schema output returned both parsed and as a string. Does not stream, call tools or functions, accept images, or use temperature or top_p (ignored); the model is chosen by this resource''s tier, not by the model field; content is not stored.
Price: 0.02 USDC on Base (x402).'
x-x402-price-usdc: '0.02'
x-x402-amount: '20000'
x-payment-info:
protocols:
- x402
price:
mode: fixed
currency: USD
amount: '0.02'
x-audience: agent-infra
x-sample-url: https://agents.writerslogic.com/api/v1/samples/chat-fast
security:
- x402: []
- apiKey: []
requestBody:
required: true
content:
application/json:
schema:
type: object
additionalProperties: false
required:
- messages
properties:
messages:
type: array
minItems: 1
maxItems: 64
description: Conversation, oldest first; the last message must have role user. At most 200000 characters in total. System messages are joined into the instructions.
items:
type: object
additionalProperties: false
required:
- role
- content
properties:
role:
type: string
enum:
- system
- user
- assistant
content:
type: string
minLength: 1
maxLength: 100000
max_tokens:
type: integer
minimum: 1
description: Upper bound on the reply in tokens; defaults to 1024. A value above the tier cap is rejected with 400.
response_format:
type: object
additionalProperties: false
required:
- type
description: 'Either {"type":"text"} (default) or {"type":"json_schema","json_schema":{name,schema}}. The schema is always enforced strictly: root object, every property required, additionalProperties false, keywords limited to type, description, properties, required, additionalProperties, items, enum.'
properties:
type:
type: string
enum:
- text
- json_schema
json_schema:
type: object
additionalProperties: false
required:
- name
- schema
properties:
name:
type: string
pattern: ^[A-Za-z0-9_-]{1,64}$
schema:
type: object
description: Strict JSON Schema for the reply.
strict:
type: boolean
description: Accepted for OpenAI compatibility; strict mode is always on.
model:
type: string
maxLength: 200
description: 'Accepted and ignored: the hub routes by tier (the resource you paid for). Echoed as requested_model.'
temperature:
type: number
description: Accepted and ignored.
top_p:
type: number
description: Accepted and ignored.
example:
messages:
- role: system
content: Answer in one sentence.
- role: user
content: What does an x402 receipt prove?
max_tokens: 200
responses:
'200':
description: Paid result with provenance
content:
application/json:
schema:
type: object
properties:
data:
type: object
properties:
id:
type: string
object:
type: string
enum:
- chat.completion
created:
type: integer
description: Epoch seconds.
model:
type: string
description: Model that served the request.
provider:
type: string
requested_model:
anyOf:
- type: string
- type: 'null'
choices:
type: array
items:
type: object
properties:
index:
type: integer
message:
type: object
properties:
role:
type: string
enum:
- assistant
content:
type: string
parsed:
anyOf:
- type: object
- type: 'null'
description: The reply parsed against your schema in json_schema mode; null in text mode.
required:
- role
- content
- parsed
additionalProperties: false
finish_reason:
type: string
enum:
- stop
- length
required:
- index
- message
- finish_reason
additionalProperties: false
usage:
type: object
properties:
prompt_tokens:
type: integer
completion_tokens:
type: integer
total_tokens:
type: integer
source:
type: string
enum:
- provider
- estimated
description: 'estimated: gpt-tokenizer count, used when the provider reported no usage.'
required:
- prompt_tokens
- completion_tokens
- total_tokens
- source
additionalProperties: false
receipt:
type: object
description: 'Hashes that the hub''s signed envelope binds to this answer: sha256 of the JCS form of your messages, of your response_format (null in text mode), and of the reply content.'
properties:
messages_sha256:
type: string
response_format_sha256:
anyOf:
- type: string
- type: 'null'
content_sha256:
type: string
tier:
type: string
enum:
- fast
- standard
- deep
required:
- messages_sha256
- response_format_sha256
- content_sha256
- tier
additionalProperties: false
attempts:
type: array
description: Providers tried in order, with the outcome of each.
items:
type: object
properties:
provider:
type: string
model:
type: string
outcome:
type: string
required:
- provider
- model
- outcome
additionalProperties: false
limits:
type: object
properties:
input_tokens_max:
type: integer
max_tokens_max:
type: integer
note:
type: string
required:
- input_tokens_max
- max_tokens_max
- note
additionalProperties: false
required:
- id
- object
- created
- model
- provider
- requested_model
- choices
- usage
- receipt
- attempts
- limits
additionalProperties: false
_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:
- Chat Fast
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