# Protocol Message Formats

This document defines the message formats used for communication between AITBC network components.

## Overview

AITBC uses JSON-based messages for all inter-component communication:
- **Client → Coordinator**: Job requests
- **Coordinator → Miner**: Job assignments
- **Miner → Coordinator**: Job results
- **Coordinator → Client**: Receipts

## Message Types

### Job Request

Sent by clients to submit a new job.

```json
{
  "type": "job_request",
  "version": "1.0",
  "timestamp": "2026-01-24T15:00:00Z",
  "payload": {
    "prompt": "Explain quantum computing",
    "model": "llama3.2",
    "params": {
      "max_tokens": 256,
      "temperature": 0.7,
      "top_p": 0.9,
      "stream": false
    },
    "client_id": "ait1client...",
    "nonce": "abc123"
  },
  "signature": {
    "alg": "Ed25519",
    "key_id": "client-key-001",
    "sig": "base64..."
  }
}
```

| Field | Type | Required | Description |
|-------|------|----------|-------------|
| `type` | string | yes | Message type identifier |
| `version` | string | yes | Protocol version |
| `timestamp` | ISO8601 | yes | Message creation time |
| `payload.prompt` | string | yes | Input text |
| `payload.model` | string | yes | Model identifier |
| `payload.params` | object | no | Model parameters |
| `payload.client_id` | string | yes | Client address |
| `payload.nonce` | string | yes | Unique request identifier |
| `signature` | object | no | Optional client signature |

### Job Assignment

Sent by coordinator to assign a job to a miner.

```json
{
  "type": "job_assignment",
  "version": "1.0",
  "timestamp": "2026-01-24T15:00:01Z",
  "payload": {
    "job_id": "job-abc123",
    "prompt": "Explain quantum computing",
    "model": "llama3.2",
    "params": {
      "max_tokens": 256,
      "temperature": 0.7
    },
    "client_id": "ait1client...",
    "deadline": "2026-01-24T15:05:00Z",
    "reward": 5.0
  },
  "coordinator_id": "coord-eu-west-1"
}
```

| Field | Type | Required | Description |
|-------|------|----------|-------------|
| `payload.job_id` | string | yes | Unique job identifier |
| `payload.deadline` | ISO8601 | yes | Job must complete by this time |
| `payload.reward` | number | yes | AITBC reward for completion |
| `coordinator_id` | string | yes | Assigning coordinator |

### Job Result

Sent by miner after completing a job.

```json
{
  "type": "job_result",
  "version": "1.0",
  "timestamp": "2026-01-24T15:00:05Z",
  "payload": {
    "job_id": "job-abc123",
    "miner_id": "ait1miner...",
    "result": "Quantum computing is a type of computation...",
    "result_hash": "sha256:abc123...",
    "metrics": {
      "tokens_generated": 150,
      "inference_time_ms": 2500,
      "gpu_memory_used_mb": 4096
    }
  },
  "signature": {
    "alg": "Ed25519",
    "key_id": "miner-key-001",
    "sig": "base64..."
  }
}
```

| Field | Type | Required | Description |
|-------|------|----------|-------------|
| `payload.result` | string | yes | Generated output |
| `payload.result_hash` | string | yes | SHA-256 hash of result |
| `payload.metrics` | object | no | Performance metrics |
| `signature` | object | yes | Miner signature |

### Receipt

Generated by coordinator after job completion.

```json
{
  "type": "receipt",
  "version": "1.0",
  "timestamp": "2026-01-24T15:00:06Z",
  "payload": {
    "receipt_id": "rcpt-20260124-001234",
    "job_id": "job-abc123",
    "provider": "ait1miner...",
    "client": "ait1client...",
    "units": 2.5,
    "unit_type": "gpu_seconds",
    "price": 5.0,
    "model": "llama3.2",
    "started_at": 1737730801,
    "completed_at": 1737730805,
    "result_hash": "sha256:abc123..."
  },
  "signature": {
    "alg": "Ed25519",
    "key_id": "coord-key-001",
    "sig": "base64..."
  }
}
```

See [Receipt Specification](receipt-spec.md) for full details.

### Miner Registration

Sent by miner to register with coordinator.

```json
{
  "type": "miner_registration",
  "version": "1.0",
  "timestamp": "2026-01-24T14:00:00Z",
  "payload": {
    "miner_id": "ait1miner...",
    "capabilities": ["llama3.2", "llama3.2:1b", "codellama"],
    "gpu_info": {
      "name": "NVIDIA RTX 4090",
      "memory_gb": 24,
      "cuda_version": "12.1",
      "driver_version": "535.104.05"
    },
    "endpoint": "http://miner.example.com:8080",
    "max_concurrent_jobs": 4
  },
  "signature": {
    "alg": "Ed25519",
    "key_id": "miner-key-001",
    "sig": "base64..."
  }
}
```

### Heartbeat

Sent periodically by miners to indicate availability.

```json
{
  "type": "heartbeat",
  "version": "1.0",
  "timestamp": "2026-01-24T15:01:00Z",
  "payload": {
    "miner_id": "ait1miner...",
    "status": "available",
    "current_jobs": 1,
    "gpu_utilization": 45.5,
    "memory_used_gb": 8.2
  }
}
```

| Status | Description |
|--------|-------------|
| `available` | Ready to accept jobs |
| `busy` | Processing at capacity |
| `maintenance` | Temporarily unavailable |
| `offline` | Shutting down |

### Error

Returned when an operation fails.

```json
{
  "type": "error",
  "version": "1.0",
  "timestamp": "2026-01-24T15:00:02Z",
  "payload": {
    "error_code": "JOB_NOT_FOUND",
    "message": "Job with ID job-xyz does not exist",
    "details": {
      "job_id": "job-xyz"
    }
  },
  "request_id": "req-123"
}
```

## Message Validation

### Required Fields

All messages MUST include:
- `type` - Message type identifier
- `version` - Protocol version (currently "1.0")
- `timestamp` - ISO8601 formatted creation time
- `payload` - Message-specific data

### Signature Verification

For signed messages:
1. Extract `payload` as canonical JSON (sorted keys, no whitespace)
2. Compute SHA-256 hash of canonical payload
3. Verify signature using specified algorithm and key

```python
import json
import hashlib
from nacl.signing import VerifyKey

def verify_message(message: dict, public_key: bytes) -> bool:
    payload = message["payload"]
    signature = message["signature"]
    
    # Canonical JSON
    canonical = json.dumps(payload, sort_keys=True, separators=(',', ':'))
    payload_hash = hashlib.sha256(canonical.encode()).digest()
    
    # Verify
    verify_key = VerifyKey(public_key)
    try:
        verify_key.verify(payload_hash, bytes.fromhex(signature["sig"]))
        return True
    except Exception:
        return False
```

### Timestamp Validation

- Messages with timestamps more than 5 minutes in the future SHOULD be rejected
- Messages with timestamps more than 24 hours in the past MAY be rejected
- Coordinators SHOULD track nonces to prevent replay attacks

## Transport

### HTTP/REST

Primary transport for client-coordinator communication:
- Content-Type: `application/json`
- UTF-8 encoding
- HTTPS required in production

### WebSocket

For real-time miner-coordinator communication:
- JSON messages over WebSocket frames
- Ping/pong for connection health
- Automatic reconnection on disconnect

## Versioning

Protocol version follows semantic versioning:
- **Major**: Breaking changes
- **Minor**: New features, backward compatible
- **Patch**: Bug fixes

Clients SHOULD include supported versions in requests.
Servers SHOULD respond with highest mutually supported version.