aminghadersohi opened a new pull request, #36271:
URL: https://github.com/apache/superset/pull/36271
### SUMMARY
This PR fixes FastMCP validation errors when Claude Code sends
double-serialized JSON strings as request parameters. All MCP tools using the
`@parse_request` decorator have been updated to accept both string and object
formats.
**Problem:** Claude Code serializes tool requests as JSON strings (e.g.,
`'{"page": 1}'`) instead of native objects, causing FastMCP to fail validation
before the `@parse_request` decorator can parse them.
**Solution:** Updated type hints from `RequestModel` to `str | RequestModel`
for all 19 MCP tools, allowing FastMCP to accept strings while the decorator
handles parsing.
**Changes:**
- Updated 19 MCP tool function signatures to accept `str | RequestModel`
type hints
- Updated test to verify string filters are now properly parsed to objects
- Maintains backward compatibility with native object requests
- Allows `@parse_request` decorator to handle string-to-object conversion
properly
**Affected tools:**
- Chart tools: `list_charts`, `get_chart_info`, `generate_chart`,
`update_chart`, `update_chart_preview`, `get_chart_preview`,
`get_chart_available_filters`
- Dashboard tools: `list_dashboards`, `get_dashboard_info`,
`add_chart_to_existing_dashboard`, `generate_dashboard`,
`get_dashboard_available_filters`
- Dataset tools: `list_datasets`, `get_dataset_info`,
`get_dataset_available_filters`
- SQL Lab tools: `execute_sql`, `open_sql_lab_with_context`
- System tools: `get_instance_info`
- Explore tools: `generate_explore_link`
### BEFORE/AFTER SCREENSHOTS OR ANIMATED GIF
N/A - Backend change only
### TESTING INSTRUCTIONS
1. Run the updated test to verify string parsing works:
```bash
pytest
tests/unit_tests/mcp_service/dashboard/tool/test_dashboard_tools.py::test_list_dashboards_with_string_filters
-xvs
```
2. Test with Claude Code MCP client:
- Start MCP server
- Call `list_charts` tool with parameters from Claude Code
- Verify no validation errors occur
3. Run pre-commit checks:
```bash
pre-commit run --files superset/mcp_service/*/tool/*.py
tests/unit_tests/mcp_service/dashboard/tool/test_dashboard_tools.py
```
4. Verify all MCP unit tests pass:
```bash
pytest tests/unit_tests/mcp_service/ -xvs
```
### ADDITIONAL INFORMATION
- [ ] Has associated issue: Related to Claude Code issue with
double-serialized requests
- [ ] Required feature flags: None
- [ ] Changes UI: No
- [ ] Includes DB Migration: No
- [ ] Introduces new feature or API: No (bug fix to existing MCP tools)
- [ ] Removes existing feature or API: No
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