update readmes

ChatAvatarSetter/README.md

@@ -1,9 +1,41 @@
 # ChatAvatarSetter
 
-This bot will set the chat avatar based on the image sent to bot
+A bot that updates a group or channel's avatar using a photo sent to the bot.
+
+## Functionality
+
+When the bot receives a photo message, it downloads the highest-resolution version of the photo
+and sets it as the chat photo for the chat the message was sent from. If the operation fails (e.g.,
+due to missing admin rights), the bot sends an error message back to the user.
+
+## Arguments
+
+| Position | Value | Description |
+|----------|-------|-------------|
+| 1 | `BOT_TOKEN` | Telegram bot token |
+
+Optional arguments (any order after the token):
+
+| Value | Description |
+|-------|-------------|
+| `debug` | Enable verbose debug logging |
+| `testServer` | Connect to the Telegram test server instead of production |
+
+## Bot Commands
+
+None.
+
+## Capabilities
+
+- Downloads the largest available photo size from the incoming message
+- Calls `setChatPhoto` to apply the downloaded image as the chat's avatar
+- Returns a user-facing error message if the update fails
+- Runs via long polling
 
 ## Launch
 
 ```bash
 ../gradlew run --args="BOT_TOKEN"
 ```
+
+> **Note:** The bot must be an administrator with *Change group info* permission in the target chat.