Cortex-Inara/docs/NEXTCLOUD_TALK_BOT.md

# Nextcloud Talk Bot Integration

Cortex connects to Nextcloud Talk as a bot — each Cortex user gets their own webhook endpoint routed to their chosen persona.

**Status:** Live and confirmed working (2026-03-20); per-user routing added 2026-03-27

---

## Prerequisites

- Access to the Nextcloud server (Docker exec or SSH)
- The Cortex server reachable at a public HTTPS URL
- The user pre-registered in Cortex (`manage_passwords.py invite`)

---

## Per-User Setup

### 1. Create the user's `channels.json`

Create `home/{username}/channels.json` on the Cortex server:

```json
{
  "nextcloud": {
    "persona": "inara",
    "url": "https://cloud.dgrzone.com",
    "bot_secret": "<a secret you choose — must match the occ install command>",
    "timeout": 55
  }
}
```

- **`persona`** — which persona responds (must exist under `home/{username}/persona/`)
- **`url`** — base URL of the Nextcloud instance
- **`bot_secret`** — a shared HMAC secret; you choose this value and use it in both `channels.json` and the `occ` install command
- **`timeout`** — seconds to wait for the LLM before sending a timeout message (NC Talk is async, so 55s is safe)

### 2. Register the bot in Nextcloud

Run on the Nextcloud server (inside the Docker container):

```bash
docker exec -it --user www-data <nc-app-container> php /var/www/html/occ talk:bot:install \
  "{persona_name}" \
  "<bot_secret from channels.json>" \
  "https://cortex.dgrzone.com/webhook/nextcloud/{username}" \
  --feature webhook --feature response --feature reaction
```

After installing, enable the bot in each Talk conversation via the conversation settings UI (three-dot menu → Bots).

To list installed bots and verify registration:

```bash
docker exec -it --user www-data <nc-app-container> php /var/www/html/occ talk:bot:list
```

To remove a bot (e.g. to re-register with a new secret or URL):

```bash
docker exec -it --user www-data <nc-app-container> php /var/www/html/occ talk:bot:remove <bot-id>
```

---

## How It Works

1. User sends a message in Talk → Nextcloud POSTs a signed webhook to `/webhook/nextcloud/{username}`
2. Cortex reads the user's `channels.json`, verifies the incoming HMAC signature
3. Sets the persona context, builds the system prompt, runs the LLM in a `BackgroundTask`
4. Returns HTTP 200 immediately (prevents Nextcloud from disabling the bot due to slow response)
5. Cortex POSTs the reply to `/ocs/v2.php/apps/spreed/api/v1/bot/{token}/message` with its own HMAC signature

---

## HMAC Signing — Critical Detail

**Incoming and outgoing signatures use different message construction.** This is the most common source of 401 errors.

### Incoming (Nextcloud → Cortex)

Nextcloud signs its outgoing webhook with `HMAC-SHA256(secret, random + raw_body)`:

```python
expected = hmac.new(
    secret.encode(),
    (random_header + body.decode("utf-8")).encode(),
    hashlib.sha256,
).hexdigest()
```

### Outgoing (Cortex → Nextcloud)

When Cortex posts a reply, Nextcloud verifies the signature against the *parsed message string*, not the raw body. This is because `BotController::sendMessage` passes the parsed `$message` parameter to `checksumVerificationService::validateRequest`, not `$request->getContent()`.

```python
sig = hmac.new(
    secret.encode(),
    (random_str + message).encode("utf-8"),  # message text only, NOT json.dumps({"message": ...})
    hashlib.sha256,
).hexdigest()
```

Wrong (causes persistent outgoing 401):
```python
# DON'T sign the full JSON body:
sig = hmac.new(secret.encode(), (random_str + '{"message": "..."}').encode(), hashlib.sha256).hexdigest()
```

---

## Nginx

The `/webhook/` prefix is already public in `auth_middleware.py`. If Nginx applies basic auth or IP restrictions, add a `location` block before the default auth block:

```nginx
location ^~ /webhook/ {
    proxy_pass http://127.0.0.1:8000;
    proxy_set_header Host $host;
    proxy_set_header X-Real-IP $remote_addr;
}
```

---

## Triggering the Bot

- **@mention** — prefix the message with `@{persona_name}`; the prefix is stripped before sending to the LLM
- **Any message** in a conversation where the bot is enabled — all messages are forwarded, not just @mentions

---

## Troubleshooting

| Symptom | Cause | Fix |
|---|---|---|
| 404 on the webhook | `channels.json` missing or no `nextcloud` key | Create/check `home/{username}/channels.json` |
| Webhook not received | Bot not enabled for conversation | Enable in Talk conversation settings (Bots) |
| Incoming 401 | `bot_secret` in `channels.json` doesn't match `occ install` secret | Re-register with matching secret |
| Reply POST returns 401 (first try) | HMAC computed over wrong data | Sign `random + message_text` only (not raw JSON body) |
| Reply POST returns 401 (persistent) | Brute force protection triggered | `occ security:bruteforce:reset <cortex-IP>` |
| Bot auto-disabled by Nextcloud | Webhook held open too long | Verify `BackgroundTasks` is used — Cortex returns 200 immediately |
| Claude falls back to Gemini | Stale/expired auth token | Run `claude auth login`; token is auto-refreshed from `~/.claude/.credentials.json` |
| No response at all | Nginx blocking the path | Add a `location ^~ /webhook/` block before any auth block |