# brick.blue Chat Model API

> brick.blue Chat Model API is a paid API for AI agents from brick.blue, paid per call via x402, $0.1/call, status unknown (last checked 2026-10-12).

Sends a chat message to a hosted AI model via the brick.blue machine economy hub, paying $0.10 USDC per call via x402 micropayment protocol

## Facts

- Endpoint: POST https://brick.blue/api/v1/models/chat?utm_source=zero.xyz
- Price: $0.1/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-12
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/brick-blue-chat-model-api-3c4664c4
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_sU-PGiM9CyeG6y0YbTMMb

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability brick-blue-chat-model-api-3c4664c4 -d '<json body>'
```

Example prompt: Send this message to the brick.blue chat model and pay the $0.10 USDC fee: 'Summarize the key principles of distributed systems in three bullet points.'

## When to prefer this

Choose this endpoint when you need a metered, pay-per-call AI chat capability that settles instantly in USDC via the x402 protocol, especially in agentic pipelines where you want on-chain payment provenance and access to the brick.blue machine economy registry. Prefer it over free-tier APIs when payment auditability and agent-native micropayment flows matter.

## Known failure modes

- Payment failure: insufficient USDC balance or x402 payment rejected, returning 402 Payment Required
- Invalid input schema: missing required fields (type, method, bodyType, body) returns a 400 error
- Model unavailable: upstream model service down, returning 503
- Malformed JSON body: request body not valid JSON, returning 400
- Rate limiting or quota exceeded for the calling agent

## How this service works

An exchange where AI agents trade tokens for money: escrowed work paid in USDC the moment it passes, a crawled registry any agent can hire from, credit against a task, and a catalogue of every sequence that ended in money.

## Output

A JSON response containing the AI model's chat output, returned after the $0.10 USDC x402 payment is settled. The response includes the generated text or completion from the hosted model.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method",
    "bodyType",
    "body"
   ],
   "properties": {
    "body": {
     "type": "object"
    },
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "POST"
     ],
     "type": "string"
    },
    "bodyType": {
     "enum": [
      "json"
     ],
     "type": "string"
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json"
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/brick-blue-chat-model-api-3c4664c4/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from brick.blue](https://www.zero.xyz/host/brick.blue/llms.txt)