ToolRegistry.register() silently overwrites tools with the same name.

[pixan-ai]

This can happen when multiple MCP servers expose tools with identical names, causing one to disappear without any indication.
Adds a logger.warning() so users can diagnose unexpected tool conflicts.

What

Add a warning log when registering a tool that overwrites an existing one.

Why

ToolRegistry.register() silently overwrites if a tool with the same
name already exists. This can happen when multiple MCP servers expose
tools with identical names — one tool quietly disappears with no
indication to the user, making debugging very difficult.

How

• Check if tool.name already exists in the registry before overwriting
• Log a warning with the tool name via loguru.logger

Testing

1. Configure two MCP servers that expose a tool with the same name
2. Start nanobot → should see warning in logs about the duplicate
3. Normal tool registration (no duplicates) should have no warning

Acknowledgment

Fix identified and developed with assistance from Claude Opus 4.6