aminghadersohi opened a new pull request, #37309:
URL: https://github.com/apache/superset/pull/37309
### SUMMARY
Flask-AppBuilder deprecated `appbuilder.app` - it now returns a `LocalProxy`
to `current_app` instead of the actual Flask app instance.
**Root Cause:**
The previous code in `superset/mcp_service/flask_singleton.py` checked
`appbuilder.app is not None` which **always returned True** because it compared
a `LocalProxy` object (not `None`) rather than the resolved value. This caused
the code to store the `LocalProxy` instead of the actual Flask app.
When MCP tools later called `app.app_context()` outside of a Flask context
(e.g., in HTTP server mode with uvicorn), the LocalProxy couldn't resolve,
causing:
```
RuntimeError: Working outside of application context.
This typically means that you attempted to use functionality that needed
the current application. To solve this, set up an application context
with app.app_context().
```
**Fix:**
- Check `appbuilder._session is not None` to properly detect if appbuilder
was initialized via `init_app()`
- Use `current_app._get_current_object()` to get the actual Flask app
instance when in an app context
- Create a minimal Flask app when not in an app context (standalone MCP
server mode)
### BEFORE/AFTER SCREENSHOTS OR ANIMATED GIF
**Before:**
```
[01/21/26 11:46:33] Error calling tool 'health_check'
RuntimeError: Working outside of application context.
```
**After:**
```
Calling health_check tool...
SUCCESS! Result: <fastmcp.tools.tool.ToolResult object at 0x12e3194c0>
INFO:superset.mcp_service.system.tool.health_check:Health check completed
successfully
```
### TESTING INSTRUCTIONS
1. Start the MCP server in HTTP mode:
```bash
superset mcp run
```
2. Call the `health_check` tool (or any MCP tool) - it should now work
without the "Working outside of application context" error
3. Alternatively, test programmatically:
```python
import asyncio
from superset.mcp_service.app import mcp
tools = mcp._tool_manager._tools
health_check_tool = tools.get('health_check')
result = asyncio.run(health_check_tool.run(arguments={}))
print(result) # Should succeed
```
### ADDITIONAL INFORMATION
- [ ] Has associated issue:
- [ ] Required feature flags:
- [ ] Changes UI
- [ ] Includes DB Migration (follow approval process in
[SIP-59](https://github.com/apache/superset/issues/13351))
- [ ] Migration is atomic, supports rollback & is backwards-compatible
- [ ] Confirm DB migration upgrade and downgrade tested
- [ ] Runtime estimates and downtime expectations provided
- [ ] Introduces new feature or API
- [ ] Removes existing feature or API
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