docs(readme): add matrix e2ee implications note

README.md

@@ -104,6 +104,7 @@ nanobot onboard
 **2. Configure** (`~/.nanobot/config.json`)
 
 For OpenRouter - recommended for global users:
+
 ```json
 {
   "providers": {
@@ -166,19 +167,21 @@ nanobot agent -m "Hello from my local LLM!"
 
 ## 💬 Chat Apps
 
-Talk to your nanobot through Telegram, Discord, WhatsApp, Feishu or Matrix(Element) — anytime, anywhere.
+Talk to your nanobot through Telegram, Discord, WhatsApp, Feishu, DingTalk, or Matrix (Element) — anytime, anywhere.
 
 | Channel              | Setup                              |
-|---------|-------|
+| -------------------- | ---------------------------------- |
 | **Telegram**         | Easy (just a token)                |
 | **Discord**          | Easy (bot token + intents)         |
 | **WhatsApp**         | Medium (scan QR)                   |
 | **Feishu**           | Medium (app credentials)           |
+| **Matrix (Element)** | Medium (homeserver + access token) |
 
 <details>
 <summary><b>Telegram</b> (Recommended)</summary>
 
 **1. Create a bot**
+
 - Open Telegram, search `@BotFather`
 - Send `/newbot`, follow prompts
 - Copy the token
@@ -211,15 +214,18 @@ nanobot gateway
 <summary><b>Discord</b></summary>
 
 **1. Create a bot**
+
 - Go to https://discord.com/developers/applications
 - Create an application → Bot → Add Bot
 - Copy the bot token
 
 **2. Enable intents**
+
 - In the Bot settings, enable **MESSAGE CONTENT INTENT**
 - (Optional) Enable **SERVER MEMBERS INTENT** if you plan to use allow lists based on member data
 
 **3. Get your User ID**
+
 - Discord Settings → Advanced → enable **Developer Mode**
 - Right-click your avatar → **Copy User ID**
 
@@ -238,6 +244,7 @@ nanobot gateway
 ```
 
 **5. Invite the bot**
+
 - OAuth2 → URL Generator
 - Scopes: `bot`
 - Bot Permissions: `Send Messages`, `Read Message History`
@@ -251,6 +258,67 @@ nanobot gateway
 
 </details>
 
+<details>
+<summary><b>Matrix (Element)</b></summary>
+
+Uses Matrix sync via `matrix-nio` (including inbound media support).
+
+**1. Create/choose a Matrix account**
+
+- Create or reuse a Matrix account on your homeserver (for example `matrix.org`).
+- Confirm you can log in with Element.
+
+**2. Get credentials**
+
+- You need:
+  - `userId` (example: `@nanobot:matrix.org`)
+  - `accessToken`
+  - `deviceId` (recommended so sync tokens can be restored across restarts)
+- You can obtain these from your homeserver login API (`/_matrix/client/v3/login`) or from your client's advanced session settings.
+
+**3. Configure**
+
+```json
+{
+  "channels": {
+    "matrix": {
+      "enabled": true,
+      "homeserver": "https://matrix.org",
+      "userId": "@nanobot:matrix.org",
+      "accessToken": "syt_xxx",
+      "deviceId": "NANOBOT01",
+      "allowFrom": [],
+      "groupPolicy": "open",
+      "groupAllowFrom": [],
+      "allowRoomMentions": false,
+      "maxInboundMediaBytes": 20971520
+    }
+  }
+}
+```
+
+> `allowFrom`: Empty allows all senders; set user IDs to restrict access.
+> `groupPolicy`: `open`, `mention`, or `allowlist`.
+> `groupAllowFrom`: Room allowlist used when `groupPolicy` is `allowlist`.
+> `allowRoomMentions`: If `true`, accepts `@room` (`m.mentions.room`) in mention mode.
+> `maxInboundMediaBytes`: Max inbound attachment size in bytes (default `20MB`).
+
+> [!NOTE]
+> Matrix E2EE implications:
+>
+> - Keep a persistent `matrix-store` and stable `deviceId`; otherwise encrypted session state can be lost after restart.
+> - In newly joined encrypted rooms, initial messages may fail until Olm/Megolm sessions are established.
+> - The bot currently sends with `ignore_unverified_devices=true` (more compatible, less strict than verified-only sending).
+> - Changing `accessToken`/`deviceId` effectively creates a new device and may require session re-establishment.
+
+**4. Run**
+
+```bash
+nanobot gateway
+```
+
+</details>
+
 <details>
 <summary><b>WhatsApp</b></summary>
 
@@ -294,6 +362,7 @@ nanobot gateway
 Uses **WebSocket** long connection — no public IP required.
 
 **1. Create a Feishu bot**
+
 - Visit [Feishu Open Platform](https://open.feishu.cn/app)
 - Create a new app → Enable **Bot** capability
 - **Permissions**: Add `im:message` (send messages)
@@ -339,6 +408,7 @@ nanobot gateway
 Uses **Stream Mode** — no public IP required.
 
 **1. Create a DingTalk bot**
+
 - Visit [DingTalk Open Platform](https://open-dev.dingtalk.com/)
 - Create a new app -> Add **Robot** capability
 - **Configuration**:
@@ -379,11 +449,12 @@ Config file: `~/.nanobot/config.json`
 ### Providers
 
 > [!TIP]
+>
 > - **Groq** provides free voice transcription via Whisper. If configured, Telegram voice messages will be automatically transcribed.
 > - **Zhipu Coding Plan**: If you're on Zhipu's coding plan, set `"apiBase": "https://open.bigmodel.cn/api/coding/paas/v4"` in your zhipu provider config.
 
 | Provider     | Purpose                                   | Get API Key                                                          |
-|----------|---------|-------------|
+| ------------ | ----------------------------------------- | -------------------------------------------------------------------- |
 | `openrouter` | LLM (recommended, access to all models)   | [openrouter.ai](https://openrouter.ai)                               |
 | `anthropic`  | LLM (Claude direct)                       | [console.anthropic.com](https://console.anthropic.com)               |
 | `openai`     | LLM (GPT direct)                          | [platform.openai.com](https://platform.openai.com)                   |
@@ -428,7 +499,7 @@ That's it! Environment variables, model prefixing, config matching, and `nanobot
 **Common `ProviderSpec` options:**
 
 | Field                    | Description                                     | Example                                  |
-|-------|-------------|---------|
+| ------------------------ | ----------------------------------------------- | ---------------------------------------- |
 | `litellm_prefix`         | Auto-prefix model names for LiteLLM             | `"dashscope"` → `dashscope/qwen-max`     |
 | `skip_prefixes`          | Don't prefix if model already starts with these | `("dashscope/", "openrouter/")`          |
 | `env_extras`             | Additional env vars to set                      | `(("ZHIPUAI_API_KEY", "{api_key}"),)`    |
@@ -440,22 +511,20 @@ That's it! Environment variables, model prefixing, config matching, and `nanobot
 
 </details>
 
-
 ### Security
 
 > [!TIP]
 > For production deployments, set `"restrictToWorkspace": true` in your config to sandbox the agent.
 
 | Option                      | Default          | Description                                                                                                                                                 |
-|--------|---------|-------------|
+| --------------------------- | ---------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------- |
 | `tools.restrictToWorkspace` | `false`          | When `true`, restricts **all** agent tools (shell, file read/write/edit, list) to the workspace directory. Prevents path traversal and out-of-scope access. |
 | `channels.*.allowFrom`      | `[]` (allow all) | Whitelist of user IDs. Empty = allow everyone; non-empty = only listed users can interact.                                                                  |
 
-
 ## CLI Reference
 
 | Command                   | Description                   |
-|---------|-------------|
+| ------------------------- | ----------------------------- |
 | `nanobot onboard`         | Initialize config & workspace |
 | `nanobot agent -m "..."`  | Chat with the agent           |
 | `nanobot agent`           | Interactive chat mode         |
@@ -547,7 +616,6 @@ PRs welcome! The codebase is intentionally small and readable. 🤗
   <img src="https://contrib.rocks/image?repo=HKUDS/nanobot&max=100&columns=12" />
 </a>
 
-
 ## ⭐ Star History
 
 <div align="center">
@@ -565,7 +633,6 @@ PRs welcome! The codebase is intentionally small and readable. 🤗
   <img src="https://visitor-badge.laobi.icu/badge?page_id=HKUDS.nanobot&style=for-the-badge&color=00d4ff" alt="Views">
 </p>
 
-
 <p align="center">
   <sub>nanobot is for educational, research, and technical exchange purposes only</sub>
 </p>