# Chat API

The Chat API enables asynchronous messaging between humans and LLM agents.
Unlike synchronous chat (ChatGPT-style), the human can leave messages while
the agent is working — the agent polls between tool calls.

## How It Works

```
Human (browser) ──POST /chat/send──▶ Synapse ◀──GET /chat/poll── Agent (LLM)
                                     │
                                     └── marks messages as read on poll
```

1. Human sends a message via the web UI (uses JWT)
2. Message is stored, marked as unread
3. Agent polls `GET /chat/poll` between tool calls
4. Poll returns all unread messages and marks them as read
5. Agent processes the message, optionally replies via `POST /chat/reply`

## Endpoints

### GET /chat/poll

Poll for new messages from the human. Returns unread messages and marks them
as read. Use this between tool calls.

```bash
curl -H "Authorization: Bearer YOUR_MIND_KEY" \
     https://synapse.schaefer.zone/chat/poll
```

Response:

```json
{
  "messages": [
    {
      "id": "msg_001",
      "role": "human",
      "content": "How's the deployment going?",
      "created_at": "2026-06-27T..."
    }
  ]
}
```

### POST /chat/reply

Send a message as the agent.

```bash
curl -X POST https://synapse.schaefer.zone/chat/reply \
  -H "Authorization: Bearer YOUR_MIND_KEY" \
  -H "Content-Type: application/json" \
  -d '{"content": "Deployment is 80% done. CI is green, just waiting for Docker push."}'
```

### POST /chat/send

Send a message as the human (requires JWT, not Mind Key).

```bash
curl -X POST https://synapse.schaefer.zone/chat/send \
  -H "Authorization: Bearer YOUR_JWT" \
  -H "Content-Type: application/json" \
  -d '{"content": "Can you check the logs?"}'
```

### GET /chat/history

Get recent chat history (both roles).

```bash
curl -H "Authorization: Bearer YOUR_MIND_KEY" \
     "https://synapse.schaefer.zone/chat/history?limit=50"
```

### GET /chat/unread

Get unread message count.

```bash
# Count unread messages from human (for agent)
curl -H "Authorization: Bearer YOUR_MIND_KEY" \
     "https://synapse.schaefer.zone/chat/unread?role=agent"

# Count unread messages from agent (for human)
curl -H "Authorization: Bearer YOUR_JWT" \
     "https://synapse.schaefer.zone/chat/unread?role=human"
```

### GET /chat/status

Get chat session status (last message timestamps, unread counts).

```bash
curl -H "Authorization: Bearer YOUR_MIND_KEY" \
     https://synapse.schaefer.zone/chat/status
```

### POST /chat/upload

Upload a file attachment for a specific message (multipart form).

```bash
curl -X POST https://synapse.schaefer.zone/chat/upload \
  -H "Authorization: Bearer YOUR_JWT" \
  -F "message_id=msg_001" \
  -F "file=@screenshot.png"
```

### GET /chat/files/:message_id

List file attachments for a message.

```bash
curl -H "Authorization: Bearer YOUR_JWT" \
     https://synapse.schaefer.zone/chat/files/msg_001
```

### GET /chat/file/:file_id

Download a file attachment.

```bash
curl -H "Authorization: Bearer YOUR_JWT" \
     https://synapse.schaefer.zone/chat/file/file_001 --output download.png
```

## Polling Pattern

> [!TIP]
> Poll every 30-60 seconds between tool calls. Don't poll more frequently —
> it wastes API quota and provides no benefit.

```python
# Pseudo-code
while working:
    messages = poll_chat()
    for msg in messages:
        process_message(msg)
        reply(f"Acknowledged: {msg.content}")
    do_one_tool_call()
```

## Next Steps

- [Tasks API](/docs/api/tasks)
- [Chat Polling Pattern](/docs/llm-cookbook/chat-polling-pattern)